Introduction - USDA Forest Service

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					Potential Risks and Impacts to Soil and Water Resources from
 Mountain Pine Beetle Mortality, Treatments and Wildfire in
           Colorado and Wyoming National Forests

                         Prepared by:

                   Joan Carlson, Hydrologist
                Rocky Mountain Regional Office

                          March, 2008

                         Approved by:

                 ___/s/ Mary H. Peterson____
                        Mary H. Peterson
                     Lead Forest Supervisor
                 Bark Beetle Steering Committee



This white paper discusses the effects of Mountain Pine Beetle (MPB) mortality, potential
treatments and wildfire on water and soil resources. It is organized around the five functional
areas in the Watershed Conservation Practices (WCP) Handbook (FSH 2509.25): Water Yield
(Hydrologic Function), Riparian Areas, Sediment Production (Sediment Control), Soil Quality
and Water Purity. The first part of the document is a literature review of potential effects and
recommended mitigation measures. Next there is a section on watershed factors to consider in
prioritizing treatment areas. This is followed by an outline of effects and mitigation measures.
And finally, in the appendix, is a list of the WCP management measures and design criteria that
would be applicable to a MPB project and a comparative table of toxicological effects of
pesticides used on MPB.

Water Yield

MacDonald and Stednick (2003) provide an overview of the processes that affect water yield
from forested lands in Colorado. In general, these processes can be summarized by the
following equation:

       Runoff = Precipitation – Evaporation – Transpiration + Change in Storage

For undisturbed forests in Colorado and Wyoming, the “Change in Storage” term is negligible on
an annual basis compared to the errors in the measurements of the other terms in the equation so
“Change in Storage” is usually ignored in water yield discussions. Therefore, water yield, or
annual runoff, is a function of the amount of annual precipitation received and the loss back to
the atmosphere via canopy interception, evaporation and transpiration. Evaporation and
transpiration are often combined into one term and called “ET”.

The equation shows that, if precipitation is held constant, runoff is directly proportional to the
amount of ET. ET in a wildland setting is mostly a function of the amount and type of
vegetation in the watershed. Any change in the amount or type of vegetation in the watershed,
either through management actions such as timber harvest or widespread natural mortality from a
bark beetle epidemic, would potentially decrease the amount of water lost to canopy interception
and ET, and therefore increase water yield. Studies in Colorado and Wyoming have shown that
at least 20 to 30 percent of the vegetation cover on a watershed needs to be affected in order to
detect a measurable change in runoff.

The equation also shows, however, that the amount of annual precipitation received needs to
exceed the annual ET in order to generate runoff. A certain amount of evaporation (from the
soil) will occur independent of the amount of interception and transpiration by the vegetative
cover. Studies have shown that the annual precipitation must be greater than 18 to 20 inches
before increases in runoff from removing vegetation can be detected. Vegetation density
increases as annual precipitation increases. At the threshold of 18 to 20 inches of annual
precipitation, the dominant source of ET loss shifts from soil evaporation to interception and
transpiration from vegetation. Above this threshold, progressively larger increases in annual
runoff occur from vegetation removal as annual precipitation increases. (A very general

equation for this relationship (in inches) is: ET = 19.1 + 0.28(P – 19.1), where ET is
evapotranspiration and P is precipitation.) This equation also means that increases in runoff
following vegetation disturbance will be greater in wetter years than in drier years. In dry years
a greater proportion of the precipitation is needed to recharge soil moisture and lost to soil
evaporation. In wetter years, less precipitation is needed for soil moisture recharge and the
excess is available for runoff.

In the high elevation, snow dominated areas of Colorado and Wyoming, snow interception by the
canopy is a much larger component of ET than in other forested areas. The snow water
equivalent (SWE) increases in direct proportion to the amount of tree canopy removed as more
snow reaches the ground rather than being trapped in the canopy where it sublimates. This
increased SWE recharges soil moisture in the early spring and the excess comes off as runoff
during snowmelt. In addition, removal of the tree canopy increases the rate of spring snowmelt
so the increased snowpack does not extend the snowmelt season. As a result, increases in water
yield from tree removal in snow-dominated areas occurs primarily on the rising limb of the
snowmelt hydrograph in the spring and there is little increase in low flows later in the year.

The size and frequency of larger flows in snow-dominated areas is increased by forest harvest,
however, there is little evidence for an increase in the highest instantaneous peak flow (i.e. flows
with a recurrence interval greater than two years). Also, the influence of vegetation removal on
peak flows is progressively reduced as the magnitude of the peak flow event increases. With
regard to timing of peak flows, there is little evidence in snow-dominated areas in Colorado and
Wyoming that the timing of peak flows is affected significantly by forest harvest.

The size of the opening and surface roughness within it also influences the magnitude of water
yield changes by affecting snow retention. While most of the increase in SWE is due to the
reduction in winter interception rather than redistribution of snow into openings, large openings
are more subject to wind scour than smaller opening. Roughness in the opening from standing
dead trees or coarse woody debris will capture and hold the snow, thus retaining water on the

Residual overstory and understory along with forest regrowth will slow the increase in water
yield from timber harvest or other disturbances over time. Hydrologic recovery rates are slower
in Colorado and Wyoming due to the relatively short growing season resulting in slower forest
regrowth. Hydrologic recovery to pre-disturbance water yields in high elevation spruce-fir and
lodgepole pine forests could take as long as 60 years.

Climate in the American West is getting warmer and drier, due to human activities. During 2003
– 2007, temperatures in the 11 western states have averaged 1.7 degrees F warmer than the
region’s 20th century average. The resulting effect on hydrology has been decreased winter
snowpacks, more winter precipitation as rain rather than snow, earlier snowmelt with peak spring
flows occurring 10 to 15 days earlier and reduced summer low streamflows. The overall effect
on precipitation in Colorado is unknown, although the Southwest U.S. is expected to receive less
precipitation and more drought (Saunders et. al. 2008). Changes in climate from anthropogenic
influences will cause changes in forest composition and runoff from Colorado and Wyoming
watersheds, however, just how much is uncertain. The direct effects of natural or anthropogenic

climate change on runoff (due to changes in precipitation) are likely to be greater than the
indirect effects to runoff from changes forest cover due to climate change (MacDonald and
Stednick 2003).

Effects of Bark Beetle Epidemic on Water Yield

The present bark beetle epidemic in Colorado and Wyoming is an unprecedented natural
disturbance that is killing trees over broad landscape areas and affects the hydrology of the
affected watersheds (Romme et al. 2007). The effects of an insect epidemic is similar to the
effects of forest harvesting in that mortality of trees eliminates their ability to transpire water,
thus increasing the amount of water potentially available for runoff (MacDonald and Stednick
2003). However, an insect epidemic is different than harvesting in many ways including the fact
that greater areas of a watershed are affected. Another difference is that unless the dead trees are
removed, the standing canopy will continue to intercept snow and other precipitation,
particularly in the first few years when the dead needles are still on the trees, reducing the
potential increase in water yield (Forest Practices Board 2007, Uunila et al. 2006, Winkler et al.

A stand level study at Fraser Experimental Forest looked at the effect of Mountain Pine Beetle
(MPB) attack on net precipitation (i.e. the amount that reaches the ground). The affected stands
were multistoried, uneven-aged stands with 52-70% infested with MPB. The amount of net
precipitation in the infested areas was not significantly different than in control areas. The
researchers speculated that the reason for this result was that needles retained on the trees
continued to intercept snow and that the multistoried, unevenaged stand structure with a live
understory mitigated the effects of the dead trees (Schmid et al. 1991).

There are very few field studies of the effects of insect epidemics on water yield documented in
the literature. Several papers provide summaries of what is known (Uunila et al. 2006, Romme
et al. 2007, Helie et al. 2005). Love (1955) documented an increase in water yield following an
Engelmann spruce beetle outbreak in the White River drainage above Meeker, Colorado in the
late 1930’s. Annual stream flow increased an average of 1.2 inches in the first 5 years following
the epidemic and an average of 2.28 inches in years 6 to 10 post-disturbance. Bethlahmy (1975)
validated Love’s work and showed that a 10% increase in water yield was still present 25 years
after the epidemic. Bethlahmy (1975) documented that the water yield increase was realized in
spring snowmelt runoff in May or June and that there was also some increase in October low
flows. The water yield increases were greater in wet years than in dry years.

Potts (1984) documented the effects of a MPB epidemic in 1975-1977 in Jack Creek in Montana.
A MPB infestation killed an estimated 35% of the total timber (lodgepole/subalpine fir) in the
watershed. Potts found that there was an estimated 15% increase in annual water yield and the
timing of the snowmelt was advanced 2 to 3 weeks. In addition, there was a 10% increase in low
flows, but little apparent increase in peak flows. However, several researchers have since
challenged Potts methodology and conclusions, and have determined the water yield increases
were not statistically significant (Uunila et al. 2006).

Cheng (1989) studied the effects of clearcut salvage in a MPB infested watershed in British
Columbia. Approximately 30% of the watershed was clearcut after a beetle epidemic in the
lodgepole pine. Cheng documented a significant average increase in annual water yield of 21%
in the post-logging period. The annual peakflow was advanced about 2 weeks in the clearcut
watershed. The greatest increase in flows was during the snowmelt season. Year to year
variations in streamflow were tied to the variability in annual precipitation, with larger flow
increases in years with greater precipitation.

There are also only a few modeling studies documented in the literature. Troendle and
Nankervis (2000) simulated a spruce bark beetle epidemic in the North Platte River watershed of
Colorado and Wyoming using the WRENNS (Water Resources Evaluation of Non-point
Silvicultural Sources) model. They assumed mortality of 50% of the sawtimber and 30% of
pole-sized trees over a 10 year period. The model showed an increase in water yield of 0.1
inches in the first year, increasing to a 2.2 inch increase in year 10 post epidemic. The model
shows the water yield increase could persist at a declining rate for as long as 60-70 years.

The interior of British Columbia is also experiencing a widespread MPB epidemic (Maloney
2005, Uunila et al. 2006, Helie et al. 2005, and Winkler et al. undated). The Forest Practices
Board commissioned a modeling study of the effects of the MPB infestation and salvage logging
on streamflows in a large watershed in interior British Columbia (Forest Practices Board 2007).
This study used a Distributed Hydrology Soil Vegetation Model (DHSVM) which determines the
water balance for each pixel in the watershed, aggregates the results and routes it to the stream.

This study modeled the effects of MPB attack (post red-needle stage) and clearcut salvage in a
388,000 acre watershed covered predominantly with lodgepole pine and minor amounts of
spruce and Douglas fir. In one modeling scenario, the study assumed 34% of the watershed was
previously harvested and 80% mortality from MPB in the remainder of the watershed, for a total
mortality in the watershed of 87%. In this scenario, the model showed significant increases in
peak flows, an advance in peak flow timing of about 2 weeks and an overall 31% increase in
annual water yield. A second scenario modeled assumed 80% of the watershed was clearcut
salvage along with 80% of the remaining 20% dead due to MPB for a total mortality in the
watershed of 97%. In this scenario, the model showed a statistically significant 92% increase in
peak flows and a 52% increase in annual water yield. In addition, the peak flow advanced 16
days. The researchers acknowledge that these results are much higher than other models or
studies have shown, but attributed that to the large size of the watershed affected and the
topography of the watershed that synchronized the snowmelt runoff into a larger peak. The
differences in magnitude of streamflow increases between these two scenarios was attributed to
continued interception of snow by the remaining dead trees reducing the water yield increases in
the scenario with less salvage harvest.

Troendle et. al. (2007) also modeled the effects of MPB infestation on lodgepole pine on
National Forest System lands in the South Platte River Basin. Three scenarios were modeled:
50 % mortality in sawtimber stands, 90 % mortality in sawtimber and pole stands and 50%
mortality in pole stands with 90% mortality in sawtimber stands. The projected annual water
yield increase over baseline was 2.8 inches in the 50% mortality scenario, 5.4 inches in the 90 %
mortality scenario and 3.6 inches in the 50 % with 90 % mortality scenario. The third scenario

(50% mortality in pole stands with 90% mortality in sawtimber stands) is considered by Forest
Service staff to be the most likely expectation of what may happen to lodgepole stands in the
South Platte River Basin over the next few years. Despite the increase in annual water yields,
Troendle et. al. conclude that peak flows are not likely to increase and may in fact decrease, as
peak flows are controlled by site specific factors including timing of snowmelt, synchronization
of streamflows from the basin and soil moisture conditions.

In summary, what can be gleaned from the research and modeling efforts described above and
the cited references, the hydrologic effects of the bark beetle epidemic will depend upon the
forest type, the number and amount of trees killed and the annual precipitation. The following
effects can be expected:
     Moderate increases in annual water yield, mostly in spring snowmelt runoff
     Minor increases in late summer to fall low flows, if any at all
     Variable responses (no change or increases) in peak flow size
     Some earlier timing of peak flows (earlier snowmelt runoff)
     Moderate effects in the early years post-epidemic, greater effects 5 to 15 years out and
        effects persisting at a decreasing rate possibly up to 60 years
     Response depends upon precipitation – greater effects (i.e. larger increases) will be seen
        in wetter years
     Presence of standing dead trees and residual live trees and understory in the watershed
        mitigates increases in water yield
     The effects of climate change on snowfall and snowmelt may make it difficult to isolate
        the specific responses of the bark beetle epidemic on water yield

Effects of Treatment of MPB affected stands on Water Yield

As noted above, studies (Cheng 1989) and modeling (Forest Practices Board 2007) have shown
greater water yield effects with the combination of harvesting and MPB mortality than from just
MPB mortality alone. Winkler and others (Undated) attribute this difference to several reasons.
The hydrologic change brought about by just MPB mortality alone is more gradual while logging
results in more immediate changes. Removal of dead trees eliminates their role in interception of
precipitation and shading which can slow snowmelt. Logging operations can result in removal
of non-pine species as well as understory vegetation including coniferous regeneration, shrubs
and herbs. Other effects include changes in amount and distribution of fine and coarse woody
debris and additional ground disturbance during harvesting and site preparation. As a result, the
initial effects of logging at the stand scale are expected to be greater than the initial effects of
MPB mortality alone.

In addition to the changes brought about by removing the dead trees, associated activities like
skidding and construction of the transportation system can also cause changes to watershed
hydrology. Overland flow is generated on compacted areas and impervious surfaces like roads,
skid trails and landings. Subsurface flow paths are intercepted by road cuts, and the road
drainage network quickly routes this runoff into the streams. The magnitude of these effects
depends upon the proportion of the area affected by the transportation system. Design of the
road drainage can mitigate effects. Insloped roads with ditches generally have greater effects
because the runoff is routed to the stream network more efficiently. Outsloped roads or roads

with rolling grades have lesser effect as runoff is dispersed to areas where it can infiltrate. While
hydrologic changes relative to roads have been documented at the road segment and hillslope
scale, they have not been confirmed at the watershed scale (MacDonald and Stednick 2003).

Literature from British Columbia offers some recommendations to mitigate hydrologic effects
associated with MPB mortality and associated salvage logging (British Columbia Ministry of
Forests and Range 2004, Forest Practices Board 2007, Maloney 2005, Summit Environmental
Consultants Ltd. 2006, and Winkler et al. Undated):
     Desynchronize runoff by salvage logging in stages utilizing a variety of cutting
        intensities and retention strategies distributed over the landscape
     Maintain a diversity of cover types and minimize post-salvage reforestation delays
        through single tree or patch retention to protect advanced regeneration as well as non-
        coniferous forest vegetation
     Leave fine and coarse woody slash on-site in openings where possible to provide surface
        roughness which would delay snowmelt, reduce wind speeds (and thus sublimation),
        maintain soil moisture and aid in site regeneration
     Construct, inspect and maintain roads to ensure natural surface and shallow subsurface
        drainage remains intact
     Upgrade drainage networks on permanent roads prior to salvage logging as necessary to
        accommodate expected increases in peak flows
     Promptly regenerate or reforest logged areas
     Minimize harvesting in riparian areas and consider wider riparian buffer widths
     Retain, where possible, all green vegetation (understory and overstory) both inside and
        outside of riparian area.
     Plan harvest units at the watershed scale to minimize road density
     Get in and out of salvage areas quickly, and deactivate any new roads wherever possible
     Consider leaving some pine stands in place where their role in maintaining water quality
        and aquatic habitat is judged to be greater than the hazards associated with beetle kill
     Increase retention within harvest units to reduce hydrologic effects of MPB mortality
        and/or salvage

Effects of Wildfire on Water Yield

There is some debate as to whether or not the MPB mortality will increase the risk of wildfire in
affected watersheds. Jenkins et. al. (2008) show that the potential for high fire intensity in
lodgepole pine stands affected by bark beetles in greatest in the first years of the epidemic due to
increases in fine fuels. The initial increase in this potential of high fire intensity decreases
shortly after the epidemic phase and increases again decades (30 to 40 years) later as snags fall
and regeneration occupies the site. Similarly, Lynch et. al. (2006) found that the increase in fire
risk over the long term is due to changes in stand structure and composition brought about by
MPB mortality rather than an increase in fuels. Some, however, downplay concern about the
potential for increased risk, arguing that the forest types affected by MPB are naturally prone to
severe, stand-replacing fire without insect outbreaks (Romme et al. 2007). What is clear,
however, is that high severity wildfire can change watershed conditions such that runoff rates are
greatly increased (MacDonald and Stednick 2003, Neary et al. 2005a, Martin 2007).

The effects of wildfire on watershed condition depend upon the amount of area burned,
watershed characteristics, suppression activities and fire severity and fire residence time. Low
severity fires rarely produce adverse effects on watershed condition while high severity fires
usually do. In addition to causing overstory mortality, high severity fire consumes the organic
surface ground cover and can alter the mineral soil such that the hydrology of the watershed is
greatly changed. Loss of protective ground cover, sealing of the soil surface and fire-induced
water repellency change the flow paths from predominantly subsurface flow in unburned
conditions to surface flow post-fire. The result is burned watersheds respond to rainfall faster,
producing higher peak flows and flash floods. This is especially true for high intensity (> 0.4
inches/hour), short duration (30 minutes to 1 hour) storms that are common in the Intermountain
West. Post-fire peak flows can be 0 to 900 times higher than pre-fire flows. Such increases in
summer storm runoff have been documented in numerous wildfire areas throughout Colorado
and Wyoming, including the 1994 Storm King fire, 1996 Buffalo Creek fire and the 2000 Bobcat
fire. Post-fire peak flow increases can persist for 10 years or more, until the vegetation and
ground cover on the burned area has recovered. (MacDonald and Stednick 2003, Neary et al.
2005a, Martin 2007).

Robichaud et. al. (2005) provides a summary of postfire rehabilitation treatments to mitigate
effects of wildfire on watershed condition and post-fire streamflows. It is more effective to
detain runoff on the hillslope than to mitigate downstream in the channel. However, in most
watersheds it is best not to do any treatments as significant investments of resources are
necessary to ensure improvement over natural watershed recovery. Therefore treatments should
be prioritized in areas where there is a high risk to life or property. The following treatments can
be used to mitigate fire effects on water yield:
     Mulching to provide at least 70 percent ground cover to provide immediate protection
        from raindrop impact and to encourage infiltration and reduce overland flow
     Contour-felled logs and contour trenching to slow runoff from slopes during low-
        intensity rainfall events, however, these treatments are not very effective during high
        intensity short duration storms (Robichaud and Elliot 2006).
     Road treatments like rolling dips, water bars, relief culverts and storm patrols reduce the
        risk of road failures during post-fire storm events.

Changes to Water Yield – “So What?”

As shown in the above discussion, any disturbance that changes the amount and distribution of
live vegetation on a watershed has the potential to increase annual water yield and peak flows.
The magnitude and timing of the water yield changes depends upon how much of the watershed
area is modified and the nature of the hydrologic processes that have been altered.

All three disturbances discussed above can change hydrologic processes over wide areas.
However, there are differences that lead to differences in effects. MPB mortality alone
eliminates the transpiration process over large areas; however, interception and evaporation
processes are still largely intact. In addition, there is no disturbance to the ground that would
change flow paths to increase watershed efficiency. The result is an increase in annual water
yield, mostly during snowmelt runoff, with little change in peak flows, i.e. a longer period of
higher snowmelt runoff flows, but little increase in the instantaneous peak flows.

Salvage logging of MPB stands changes the interception and evaporation processes, in addition
to the loss of transpiration from MPB mortality. There is ground disturbance associated with
logging as well, which can change flow paths. The result is a greater increase in annual water
yield over that experienced by MPB mortality alone, as well as an increased potential for
increases in instantaneous peak flows.

In addition to causing mortality which alters the interception and evapotranspiration processes,
wildfire also removes organic ground cover and changes soil structure, altering flow paths from
subsurface to the surface. As a result, particularly in high severity fires, there is a greater
increase in instantaneous peak flows in response to high intensity summer precipitation events.

The consequence of increases in water yield depends upon the situation. An increase in annual
water yield can be beneficial to downstream beneficial uses, such as water supply, if storage is
available to take advantage of it and the water quality is good. The drawback of increased water
yield is flood damage that can occur if the increased flows, particularly increased instantaneous
peak flows, exceed the capacity of the streams and floodplains to carry the water downstream.
Particularly vulnerable are undersized culverts and crossing structures and roads or other
structures located in floodplains. Changes in stream habitat can also occur as increased
streamflows erode weakpoints in the streambanks and rearrange sediment deposits.

Riparian Areas

Riparian areas are those lands adjacent to water bodies and are considered to be the transition
between the aquatic ecosystem and the upland terrestrial ecosystem. Riparian areas have distinct
vegetation and soil characteristics that are influenced by high water tables or the presence of near
surface water. Continuous interactions occur between riparian, aquatic and adjacent terrestrial
ecosystems through exchanges of energy, nutrients and species. A healthy, functioning riparian
area provides many values, including: shade, bank stability, fish cover, woody debris input,
storage and release of sediment, surface-ground water interactions and habitat for terrestrial and
aquatic plants and animals.

Effects of Bark Beetles on Riparian Areas

The effects of MPB mortality on riparian area structure and function depends upon the
vegetation composition of the riparian area and the amount of mortality. Riparian areas are more
likely to be composed of a mixture of overstory species. However, pine-dominated riparian
overstory are not uncommon, such as along ephemeral streams, intermittent streams and
perennial streams with steep sideslopes where upland vegetation such as lodgepole pine may
come very close to the edge of the stream. The most immediate effect of MPB mortality in the
pine dominated riparian area could be loss of stream shading as overstory trees die and lose their
needles. Loss of shading allows increased solar radiation to the stream, potentially increasing
stream temperatures. Degree of shading lost also depends upon slope and aspect of the
watershed, as stream shading may also be provided by upslope vegetation or other topographic

A second effect of MPB mortality in the riparian area is the potential for greatly increased
loadings of large woody debris (LWD) to riparian areas and stream channels as over the years
the dead trees fall down. “Tip-up mounds” from fallen trees can be a sediment source within the
riparian area, however, LWD on the ground can act as sediment traps if the tree bole is flush with
the ground surface. LWD creates habitat features in streams by creating pools and providing
overhead cover for fish. LWD affects sediment transport and flow through the stream which
affects stream channel dynamics and morphology. While there is not likely to be “too much of a
good thing” from an aquatic ecosystem perspective, too much LWD can be a problem in certain
areas where accumulations of debris plug culverts or other stream crossing structures, potentially
washing out roads.

Another indirect effect of MPB mortality on stream channels is changes to stream channel
morphology from increased flows. Generally, a healthy, functioning riparian area well
connected to its floodplain should be able to accommodate increased flows. However, increases
in flows may create problems for aquatic organism passage at closed bottom stream crossings
due to increases in flow velocity or depth inside the culvert.

The effectiveness of riparian areas for filtering sediment and nutrients following canopy
mortality are uncertain, but will likely be greater than riparian areas where soils have been
disturbed. Where dense understory vegetation and ground cover exist, these will likely trap
sediment and take up nutrients following overstory mortality. Water tables within the riparian
area may rise with increased soil moisture in the watershed due to MPB mortality which may
stimulate the expanse of riparian understory, shrub, and tree species. Change in lower slope
gorundwater table may also influence nitrogen and carbon dynamics and transfers from
terrestrial to aquatic ecosystems (C. Rhoades, pers. comm.).

Effects of Treatment of MPB affected stands on Riparian Areas

Riparian functions and values that can be affected by mechanical treatments or prescribed
burning include shade, sediment filtering, bank stability, and woody debris input. Removal of
overstory trees, even if dead, can reduce stream shading and increase stream temperatures.
Shading can also be reduced by disturbance of streamside understory vegetation. Loss of ground
cover from mechanical disturbance or consumption in a prescribed fire can reduce the riparian
area’s ability to filter sediment. Mechanical disturbance to streambanks can reduce streambank
stability and removal of overstory trees reduces the potential supply of long-term LWD inputs to
the stream system.

The Watershed Conservation Practices Handbook (FSH 2509.25) direction for treatments in
riparian areas is articulated in Management Measure 3: “In the water influence zone next to
perennial and intermittent streams, lakes, and wetlands, allow only those actions that maintain or
improve long-term stream health and riparian ecosystem condition.” The desired outcome of any
treatment completed in riparian areas should be to maintain or improve stream or riparian
condition. The WCP Handbook lists many design criteria to mitigate or minimize effects to
riparian functions and values. Applicable design criteria are listed in the appendix to this

Healthy, functioning riparian areas provide resilience to the stream system to accommodate
watershed disturbances such as widespread MPB mortality. In response to MPB outbreak,
Papdopulos (2007) recommend focusing on accelerated restoration of riparian areas, stream
corridors and wetlands using a combination of well-planned thinning, revegetation, stream
channel shading, promotion of understory vegetation and incorporating large woody material
into the stream channel. Some recommend taking a conservative approach to riparian
management in response to MPB (Summit Environmental Consultants 2006), including
expanding the width of the water influence zone (WIZ) or riparian area to mitigate potential
effects of upslope disturbances (British Columbia Ministry of Forests and Range, 2004) and
minimizing harvesting within riparian areas (Winkler et. al. undated). Where windthrow may be
an issue, consider utilizing riparian integrity protection techniques, such as feathering or topping
(Maloney 2005). Other actions that can be taken to restore riparian areas include removing or
improving roads in riparian areas to reduce connected disturbed areas (CDAs) and improving
stream crossings to pass increased flows, reduce potential for blockage by debris and to allow
improved passage for aquatic organisms.

Effects of Wildfire on Riparian Areas

Reardon et. al. (2005) describes the effects of fire on riparian areas. The severity of damage to
riparian vegetation depends upon the severity of the fire. Low severity, cool-burning prescribed
fires have less severe consequences to riparian vegetation. Severe wildfires can cause profound
damage to plant cover and litter layers. This can cause increases in streamflow velocity,
sedimentation rates and stream temperatures. Wildfire in the surrounding watershed indirectly
affects riparian areas by causing basin instability, and in steep erodible topography, can lead to
debris flows, dry ravel or landslides. Aquatic biota are also indirectly affected by wildfire with
the primary effects being ash flows, changes in hydrologic regimes and increases in suspended
sediment (Rinne and Jacoby 2005). Longer term impacts to fish from wildfires are impacts to
habitat from changes in stream temperature due to loss of plant overstory and understory
shading, increased flood peakflows and sedimentation due to landscape erosion. Increasing
stream temperatures can increase the biological activity in the stream. Increased biological
activity places greater demand on the dissolved oxygen content of the water, which is one of the
more important water quality characteristics from a biological perspective (Neary et. al. 2005b).
Increased stream temperature can also have detrimental effects by accelerating stream
eutrophication, which can adversely affect the color, taste and smell of drinking water (Neary et.
al. 2005b). Recovery of riparian vegetation reflects the combined disturbance of both the
wildfire and post-fire flooding, and together they influence the time required for revegetation or
success of postfire rehabilitation efforts. Even after severe fire, recovery in riparian zones can be
rapid, and may recover to prefire conditions within only a few years in some situations (Reardon
et. al. 2005).

Changes to Riparian Areas – “So What?”

MPB mortality is a natural disturbance in riparian areas that has some effects on riparian
functions and values, predominantly stream shading in the short term and LWD recruitment and
loading in the long term. Unwanted effects can occur in riparian areas when facilities such as
roads or stream crossings are impacted by changes in stream flows due to MPB mortality.

Treatments in riparian areas, if carefully done, can encourage restoration and rehabilitation of
riparian areas in poor condition. There may be a desire to do some fuel treatments or salvage
timber within riparian areas; however, these desires should be balanced by the needs of the
riparian area to protect the aquatic and riparian ecosystems so that the outcome is maintenance or
improvement of stream health and riparian condition. Severe wildfire would have the greatest
effects to riparian structure, function and processes through loss of vegetation and ground cover.

Sediment Production

Undisturbed forested areas in Colorado and Wyoming typically have very low erosion rates
because much of the precipitation falls as snow, infiltration rates are high and mass movements
are either infrequent or relatively inactive. Ground disturbance will generally increase soil
erosion. The amount of soil exposed, the effect on infiltration rates, slope steepness, soil type,
amount and intensity of precipitation and the type of mitigation measures applied (e.g. seeding,
mulching, or ripping) all affect the type and magnitude of soil erosion caused by management
activities. (MacDonald and Stednick 2003).

Excessive sediment from roads or other disturbed sites can have adverse effects on aquatic
habitat and other beneficial uses of water. Physical effects of increased sediment load include
changes in channel shape, sinuosity, number and quality of pools, or bed material size, all of
which affect the quantity and quality of habitat for fish and benthic invertebrates. Fine sediment
can impair the use of the water for municipal or agricultural purposes, resulting in a need for
additional treatment in order for the water to be suitable for such uses. In addition, many
nutrients and other chemical constituents are sorbed onto fine particles, so increased sediment
loads may increase the concentrations of these constituents. Increased stream temperatures and
decreased intergravel dissolved oxygen concentrations are some indirect effects that may occur
with increased sediment loads.

Effects of Bark Beetles on Sediment Production

Large areas of MPB mortality are unlikely to have direct, adverse effects on erosion and
sedimentation rates because of the lack of roads or other ground disturbance (MacDonald and
Stednick 2003, Romme 2007).

Effects of Treatment of MPB affected stands on Sediment Production

As noted above in the introduction to this section, ground disturbance will generally increase soil
erosion rates in the forest environment. Potential treatment options for treating MPB infested
stands include activities that will create ground disturbance or loss of protective ground cover:
harvest, mechanical vegetation treatments, site preparation activities and the associated roads and
transportation systems. The site disturbance from the act of felling trees is generally considered
to be minor, although use of mechanized feller bunchers can create surface disturbance. Of
greater concern are the transport of the logs to a central site, post-harvest site preparation
activities and the network of roads, skid trails and landings needed to access the stands
(MacDonald and Stednick 2003).

Unpaved roads are a major source of sediment in forested watersheds. The road prism, cutslope,
inside ditch, sidecast or fill material and areas subjected to concentrated runoff from roads are all
potential sediment sources. Erosion rates are generally highest during road construction and
generally decrease over time as disturbed areas are stabilized by revegetation or development of
an armored surface. Erosion rates may increase when roads are maintained or reconstructed as
the previously stabilized surfaces are redisturbed. Road surfaces, cutslopes and inside ditches
can continue to produce large amounts of sediment as long as traffic or road maintenance
operations prevent revegetation or surface stabilization. Even abandoned roads, if untreated, can
continue to produce substantial amounts of sediment over time as they slowly revegetate
(MacDonald and Stednick 2003).

Best Management Practices should be used to minimize increases in erosion and sediment
production from MPB treatment activities. Basic practices include avoiding sensitive terrain and
soil types, developing erosion control plans for roads and harvest activities, closing and
rehabilitating temporary use roads when no longer needed, and reclaiming pre-existing sediment
sources and connected disturbed areas to reduce sedimentation (Winkler et. al. undated, Summit
Environmental Consultants 2006, MacDonald and Stednick 2003). The appendix lists applicable
management measures and design criteria from the WCP Handbook that should be used in MPB

Like wildfire, prescribed fire can increase erosion rates if the fire severity is great enough.
Prescribed fires are designed to be less severe than wildfire and usually do not consume all of the
protective litter and duff layers over large areas. However, Best Management Practices should
be used to minimize the potential for sediment production from prescribed fires. These include
use of buffer strips along stream courses, careful location and construction of firelines, avoidance
of heavy equipment use on fragile soils and steep slopes, prompt rehabilitation and erosion
control on fire lines, and burn prescriptions designed and implemented to maintain adequate
ground cover (Neary et. al. 2005b, MacDonald and Stednick 2003).

Effects of Wildfire on Sediment Production

Increased sediment is one major water quality effect of wildfire (Martin 2007, Rhoades
2006). As noted above in the discussion of the effects of wildfire on water yield, high severity
wildfire consumes the protective organic surface ground cover and can induce water repellency
in the soil such that post-fire runoff is predominantly surface overland flow. This, combined
with high intensity, short duration storms common in the Intermountain West, can lead to greatly
increased erosion rates from high severity burned areas (MacDonald and Stednick 2003, Neary
et. al. 2005a, Neary et. al. 2005b, Martin 2007). Studies have shown that at least 80% of the
annual post-fire erosion is driven by summer convective storms with rainfall intensities of 10
mm (0.4 inches) per hour (MacDonald and Stednick 2003). Burned areas are most vulnerable to
surface erosion immediately after the fire and during extreme rainfall events (Elliott and Vose

The magnitude and intensity of the wildfire influences the magnitude and persistence of
increased post-fire erosion. Studies of post-fire erosion in the Colorado Front Range have shown
large differences in sediment production with fire severity. Low severity fires may have no

increase in erosion; whereas high severity burned areas produce much greater sediment than low
severity burns. (MacDonald and Stednick 2003). Observations on the Overland and Picnic Rock
fires on the Arapaho-Roosevelt NF show sediment movement initiated by thundershowers on
moderate severity burned areas (E. Schroder, pers. comm.).

Geology and slope also play a role in post-fire sediment production (Moody et. al. 2008). The
higher post-fire erosion values reported in the literature are from fires on steep slopes and areas
of decomposing granite that readily erode. The lower values are associated with flat sites and
lower severity fires (Neary et. al. 2005b).

Increases in post-fire erosion can also result from channel incision due to the increase in post-fire
runoff and a decrease in surface roughness or from mass movements (MacDonald and Stednick
2003). There are two post-fire erosional styles recognized in Colorado: channel erosion in
granitic terrain and debris flows in sedimentary geology. Slopes in sedimentary terrain greater
than 30% slope are at risk of post-fire debris flows (Martin 2007).

Postfire sediment yields are generally the greatest in the first year or so after the fire. This is
especially true when large high-intensity rainfall events occur immediately after the fire has
exposed the soil surface (Neary 2005b). Recovery of hillslopes can be fairly rapid due to
regrowth of protective vegetation and breakdown of fire-induced water repellency. Studies on
fires in the Front Range have shown erosion rates on burned hillslopes are not significantly
different from unburned or lightly burned hillslopes four to six years after fire (MacDonald and
Stednick 2003). High erosion rates can still occur as a result of severe storm events or on sites
with particularly poor growing conditions. Drier areas with coarse-textured soils have the
slowest declines in post-fire sediment production rates due to the limited ability of these soils to
retain soil moisture and thus slower revegetation rates (MacDonald and Robichaud 2008).
Postfire channel incision and downstream sediment deposition may be much more persistent and
take many years to recover (MacDonald and Stednick 2003).

Maintaining an intact forest floor and promoting rapid vegetation recovery is critical to
minimizing the magnitude and duration of post-fire erosion and sediment delivery (Elliott and
Vose 2006). In general, postfire rehabilitation treatments can not prevent erosion, but they can
reduce overland flow amounts, site soil loss and sedimentation for some rainfall events
(Robichaud and Elliot 2006). Robichaud et. al. (2005) provides a summary of post-fire
rehabilitation treatments to mitigate post-fire erosion and sedimentation. Hillslope treatments are
the first line of defense against post-fire erosion and are designed to keep soil in place on the
hillslope and thereby prevent sediment deposition in unwanted areas. Hillslope treatments
include broadcast seeding, mulching, contour log erosion barriers, straw wattles, contour
trenching, scarification, silt fences, and geotextiles. Mulch and geotextiles are considered the
most effective hillslope treatment because they provide immediate ground cover to reduce
raindrop impact and to hold soil in place. Wheat straw is an effective erosion mitigation
technique during the first two postfire years. Other dry mulches, like wood straw and dead
needles, can also provide erosion control when ground cover is greater than 70% (Robichaud and
Elliot 2006).

Channel treatments can also be used, with extreme caution, to alter sediment movement in small
channels to protect downstream values at risk. Check dams can be made of a variety of materials,
including logs, sand bags, rocks, straw bales or straw wattles. These structures slow down water
flow and allow sediment to settle out. The sediment will gradually be released as the structure
decays over time. Grade stabilizers can be made out of logs or rocks. These structures work to
stabilize channel gradient rather than trapping sediment. Debris basins are considered a last
resort due to the great expense and necessary commitment to annual maintenance to keep them
effective. Debris basins can be used in stream systems with naturally high sediment loads to
control runoff and reduce threats to water quality, human life and property. Hillslope treatments
need to be done in conjunction with channel treatments to improve the effectiveness of in-
channel work.

Changes to Sediment Production – “So What?”

The Crimson Vegetation Management EA (US Forest Service 2004) provides a good summary
of the “so what?” for sediment production:

       “Lodgepole pine ecosystems tend to have a long fire return interval and
       experience infrequent, high severity burns associated with stand replacing fire.
       Aquatic ecosystems associated with this fire regime are subject to periodic
       episodes of very high sediment delivery following fires followed by long periods
       of relative stability. The sequence of natural processes would be for the stands to
       senesce, be attacked by insects, disease or blowdown events and then for the areas
       to burn, often in stand replacing events. Erosion and sediment levels would
       significantly increase, especially the first several years after a wildfire, and then
       decrease as vegetation recovered. Fire suppression in these watersheds may have
       reduced the frequency of severe post-fire sediment influxes but other human uses
       such as roads, timber harvest, and recreation have introduced sources of chronic,
       lower level watershed disturbance and sedimentation.”

Man caused disturbances create chronic sources of low level sedimentation that can cumulatively
overwhelm the ability of a stream system to transport and adversely affect the biological
community. Natural disturbances like severe wildfire cause acute episodes of high
sedimentation, which the aquatic systems have adapted to. However, these acute episodes of
high sedimentation can cause major problems for downstream water suppliers, more so than
chronic low level sedimentation.

MacDonald and Stednick (2003) advance the proposal that accepting small amounts of sediment
from a proactive fuels treatment program is a better policy choice over the long term than
continuing efforts to suppress wildfires and then applying marginally effective post-fire
emergency rehabilitation treatments when fires do occur. But they also note long-term
evaluations of the overall costs and benefits of repeated fuels treatments versus the effects of
wildfires have not been done.

Soil Quality

Soil properties and processes are influential in regulating the productivity of terrestrial
ecosystems and their response to natural disturbance and management activities. Soil aggregate
structure, organic matter and nutrient pools, and biogeochemical processes are critical to
sustaining this potential vegetative growth capacity. Soil productivity is impaired when these
qualities are significantly degraded either from a severe disturbance or management activity or
from a chronic effect occurring over a period of years. Severe disturbances can impair the ability
of soils to support ecosystem productivity in a number of ways including: extreme heating
associated with wildfire and slash burning; increased surface erosion and nutrient export
associated with forest floor displacement; and reduced soil gas and water exchange and root
penetration caused by physical compaction (U.S. Forest Service 1006). Degradation of soil
properties may not only impair long-term site productivity, but can also influence surface water
quality by causing greater sediment and nutrient loss to streams.

Effects of Bark Beetles on Soil Quality

Overstory mortality from the MPB epidemic is expected to have little effect on soil
displacement, compaction or erosion, since forest floor and mineral soil disturbance should be
minimal in most cases. However, soil quality can be changed in MPB stands due to changes in
organic matter, nutrient cycling and availability and biotic processes.

Little is known about how soil processes will respond to widespread canopy mortality, but
change in the conditions that control soil nutrient, carbon and moisture dynamics can be
expected. Change in soil productivity and forest regeneration are the topics of new research at
the Fraser Experimental Forest and throughout the MPB affected areas in Region 2. In a
research study proposed by Rhoades et. al. (2007), it is hypothesized that soil limitations caused
by ectomycorrhizal fungi loss, soil nitrogen dynamics and soil water availability will delay or
inhibit forest recovery in certain parts of the landscape. Root dieback associated with overstory
mortality will reduce ectomycorrhizal inocula in the soil. Ectomycorrhizal fungi help conifers
extract nutrients from the soil and are essential for seedling establishment. Microbial activity
will increase in response to the large carbon source provided by nitrogen poor needles and fine
roots in dying pine forests. The microbes will immobilize nitrogen in the soils, making it less
available for plant uptake. In addition, canopy mortality would build rather than remove forest
floor (additional litter and deadfall), which could reduce the number of optimal seedbed sites and
further limit seedling establishment. Seedling regeneration may also be inhibited by reduced
pine seed viability as well as in sites with dense understory ground cover (i.e. Vacinium spp.,
Carex spp.).

Effects of Treatment of MPB affected stands on Soil Quality

There is more known about forest and soil responses to fire and live-tree harvest than about their
response to salvage harvest in MPB affected stands. Following a fire and live-tree harvest, soil
nutrients have been shown to increase, decrease or remain unchanged depending upon the
intensity of disturbance and site conditions. As speculated above, there are a number of factors
that may reduce regeneration following widespread overstory pine mortality in untreated stands.

While there will be a reduction in ectomycorrizal fungi from overstory death, some of the other
effects on soil processes may be mitigated by light to moderate disturbance from careful salvage
logging and site preparation activities. Forest floor disturbance alters soil microbial populations
and processes, nutrient availability and cycling, and the potential for ectomycorrizal colonization
by exposing mineral seedbeds, stimulating microbial decomposition of organic residues,
increasing bacterial biomass and N mineralization and nitrification. As a result, N is more
available to tree seedlings and initial tree growth would be increased. In addition, removal of
dead overstory trees should enhance micro-site characteristics by increasing soil moisture and
temperature. Therefore, salvage harvest may provide a benefit to lodgepole regeneration in MPB
affected stands over no treatment options (Rhoades et. al. 2007).

However, more severe ground disturbance during harvest or site preparation activities will in fact
impede regeneration. Disturbance that buries or displaces soil organic layers may reduce
nutrient supplies, lower microbial biomass, reduce ectomycorrizal colonization and N
mineralization. As a result, N availability would be limited and the potential for ectomycorrizal
colonization would be low restricting regeneration on highly disturbed sites (Rhoades et. al.
2007). In addition, there could be adverse impacts to soil quality and structure from harvest, site
preparation and associated activities. There may be increases in soil compaction or erosion from
skid trails, landings or road construction. Burning massive piles of slash may cause severe
burning of soil underneath the slash pile, which can detrimentally affect soil quality by changing
soil structure and killing soil microbes in these areas. These effects will last for many years.

The WCP Handbook (FSH 2509.25) directs that Management Measures and design criteria are to
be used in projects to minimize and mitigate effects of treatments on soil quality (U.S. Forest
Service 2006). In addition, there are soil quality standards in the Soil Management Handbook
(FSH 2509.18) designed to maintain or improve the long-term inherent productive capacity of
the soil resource (U.S. Forest Service 1991). Proper use of these practices and adherence to
these standards should provide protection to soil quality during treatment activities.

Effects of Wildfire on Soil Quality

Wildfire can cause changes to soil chemical, physical and biologic properties. The basic soil
chemical property affected by soil heating during wildfire is organic matter. Soil organic matter
has a key role in nutrient cycling, cation exchange and water retention. Stored nutrients are
either volatilized or are changed into more available forms when organic matter is combusted.
Surface runoff and erosion or leaching will cause available nutrients that are not immobilized to
be lost from the site. Nitrogen is the most important nutrient affected by fire. It is easily
volatilized and can be lost from the site at low temperatures. The magnitude of soil heating and
severity of the fire determine the amount of change in organic matter and nitrogen. As nitrogen
can only be replaced by nitrogen-fixing organisms, nitrogen loss by volatilization is especially of
concern on low-fertility sites. Cations usually remain on the site in highly available forms
because they are not easily volatilized. An abundance of cations can be found in the ash
remaining on the soil surface following high severity fires (Knoepp et. al. 2005).

The transfer of heat into the soil is the most important physical process functioning during a fire.
Soil structure can be lost in a fire due to combustion of organic matter, which can occur at

relatively low temperatures. The resulting increased bulk density and reduction in soil porosity
due to loss of soil structure reduces soil productivity and soil hydrologic function, and increases
the potential for soil loss due to postfire runoff and erosion. In addition to soil structure loss,
wildfire can cause a water-repellent layer to develop within the soil. Water repellent layers form
when organic substances are moved downward into the soil by vaporization due to heating and
then condense onto soil particles. A water repellant soil condition further accelerates postfire
runoff and erosion causing extensive rill networks to form on the soil surface. Erosion by
raindrop splash is also increased by water repellency. The temperature threshold of the soil and
the severity of the fire determine the magnitude of change in soil physical properties caused by
the fire. The greatest changes in soil physical properties occur when smoldering fires burn for
long periods (DeBano et. al. 2005).

A wide range of living organisms inhabit the soil and are responsible for regulating many
biological processes important to short- and long-term productivity and sustainability of forested
ecosystems. Numerous factors including fire intensity and severity, site characteristics, and
preburn community structure determine how soil microorganisms will respond to a fire. Fire is
lethal to microorganisms and can alter habitat by destroying organic matter, altering soil
temperature and moisture regimes. Fire effects are greatest in the forest floor (litter and duff
layers) and decline rapidly with mineral soil depth. In general, however, most studies have
shown a strong resilience by microbial communities to fire. While the time required for recovery
varies in proportion to fire severity, recolonization to preburn levels is common following fire
(Busse and DeBano 2005).

One of the purposes of postfire watershed rehabilitation is to reduce the loss of soil and onsite
productivity, primarily by restoring ground cover and reducing soil erosion. Applications of
mulch and seeding are common techniques for restoring ground cover. Slash spreading and
needle cast can also provide ground cover after a fire. Scarification and ripping can be used to
break up water repellent layers and increase soil porosity to increase infiltration (Robichaud et.
al. 2005), though if poorly done can greatly increase the potential for soil erosion.

Changes to Soil Quality – “So What?”

Soil quality can be changed by disturbances in a forested stand. Widespread MPB mortality may
cause changes in soil processes and nitrogen cycling that adversely affect the ability of a site to
regenerate pine trees. Light or moderate site disturbance from salvage logging of MPB affected
stands may increase the potential for successful regeneration of these sites. However, there is a
tradeoff as soil quality can be adversely affected by harvest and site preparation activities if
BMPs and soil quality standards are not followed. Wildfire affects soil quality primarily through
soil heating which can change soil physical properties and organic matter. Erosion and nutrient
loss are the predominant effects of fire on soils.

Water Purity

Water purity, in the context of the Watershed Conservation Practices Handbook, refers to the
chemical constituents of water quality. This section covers the potential effects of bark beetles,

treatments, and wildfire on nutrients, metals and other pollutants in water quality. Sediment and
physical habitat aspects of water quality were discussed in earlier sections of this document.

Water draining from forested watersheds is typically higher in quality than water from
watersheds with other major land uses. Higher water quality results from the effective nutrient
retention by forest soils and vegetation, the small extent of soil disturbance and the limited use of
fertilizer inputs, and unaltered streamflow generation processes within undisturbed forest
watersheds. As a result, these waters are low in nutrients and suspended sediments. Forest
management activities, wildfires and other natural or anthropogenic disturbances can disrupt the
natural cycles and lead to increased concentrations of nutrients, metals or other pollutants in the
water. If detrimental changes in the quality of water draining disturbed forested lands were to
occur, this could create a need for increased treatment and purification before the water can be
used for domestic, municipal, industrial or agricultural purposes (MacDonald and Stednick

Effects of Bark Beetles on Water Purity

Very little information has been published on the effects of bark beetle infestations and mortality
on soil or water chemistry. It is expected that there would be some loss of nutrients, nitrogen in
particular, from MPB affected stands and this will be evident in nearby streams. This
expectation is based on the fact that nitrogen mineralization increases in any disturbed system
and the resulting ammonium is converted into nitrite and nitrate by nitrification. These nitrates
in the soil may then be leached and flushed into streams. MPB mortality will share some
similarity of effects to the effects of forest harvesting on water chemistry, as both reduce nutrient
uptake by vegetation, however, in contrast to harvesting, residual trees and understory species
will retain nutrients. There is also a difference in that most of the biomass remains on-site
following MPB mortality and when this organic matter decays, nutrients are returned to the soil.
It is reasonable to assume there will be some nutrient loss following MPB mortality but the
extent will depend upon nitrogen response at the site and the rate at which the system produces
nitrate. In areas where nitrification rates are high, other cations like calcium, potassium,
magnesium and aluminum may also be mobilized and lost to the stream system (Helie et. al.

Effects of Treatment of MPB affected stands on Water Purity

Treatment of MPB affected stands can affect water chemistry in two ways: through changes
stand biogeochemical cycling that can lead to nutrient loss or through the introduction of
chemical pollutants such as insecticides or hydrocarbons from accidental spills.

As noted above, stand disturbance can alter the nitrogen cycle within a stand and affect the
mobilization of other nutrients. Nutrient mobility from disturbed stands generally follows this
order: nitrogen > potassium > calcium and magnesium > phosphorus. Forest harvest will
produce larger differences in nitrogen concentrations than other constituents. Studies have
shown that increases in stream nitrogen after harvest activities are generally below drinking
water standards. Increased export of nitrogen has a short duration and is often less than

atmospheric inputs of nitrogen into the system. Typically, timber harvest will have a small
impact on nutrient concentrations in streams (Macdonald and Stednick 2003).

One strategy for protecting trees from bark beetle attack is to spray individual high-valued trees
with insecticide. There are several insecticides registered for treating individual trees, including
certain formulations of carbaryl (Sevin), permethrin, and bifenthrin (Leatherman et. al. 2007).
Carbaryl is highly toxic to aquatic invertebrates and highly to slightly toxic to fish depending
upon species. Carbaryl persists longer in acidic conditions and is moderately mobile in soils.
Carbaryl can be found in groundwater and surface water due to its widespread use and
persistence in acidic conditions (NPIC 2003). Permethrin is highly toxic to fish, but has a low
potential to move in the soil. If used according to label directions utilizing precautions to protect
water sources, permethrin poses little risk to aquatic life (NPTN 1997). Bifenthrin is very highly
toxic to fish and aquatic animals. Bifenthrin is not likely to be found in aquatic systems due to
its high affinity for soil and low water solubility. Bifenthrin poses a low risk to groundwater
contamination through leaching (Extoxnet 1995). Appendix B contains a comparative table of
toxicological and ecological effects of carbaryl, permethrin, and bifenthrin compiled by staff on
the Arapaho-Roosevelt NF. All pesticides should be used according to label directions to
prevent contamination of surface and groundwaters.

A second risk of chemical contamination of surface waters during treatment activities is
accidental spills of oil, gas or other products associated with equipment use. BMPs can be used
to reduce this risk. Practices include measure such as siting re-fueling stations in upland areas
away from surface waters, constructing berms around fueling areas and preparation of
emergency spill plans and following those provisions in event of a spill.

Effects of Wildfire on Water Purity

Sediment is the major water quality effect of wildfire (Martin 2007). However, wildfire can
affect nutrients and other chemical constituents of water quality including increasing nitrates
(Rhoades 2006), possible introduction of heavy metals from soils and geologic sources
within the burned area and introduction of fire retardant chemicals that can reach toxic levels for
aquatic organisms (Neary et. al. 2005b).

Nutrient cycling in a vegetative community is disrupted by fire. Fire causes a rapid volatilization
and dispersion of plant nutrients including N, P, K, Ca, Mg, Cu, Fe, Mn and Zn. Once the
nutrients are released from the plant matter, they are vulnerable to off-site loss through leaching
or overland flow. Reduction in plant uptake increases the potential for nutrient loss by leaching.
And the loss of vegetative cover increases the potential for loss due to erosion (Neary et. al.

Nitrogen, particularly nitrate-nitrogen (NO3-N), is highly mobile and thus is the focus of most
post-fire nutrient loss concern. Fire accelerates mineralization and nitrification of nitrogen,
coupled with reduced plant demand and increased soil microbial activity, increases mobilization
of NO3-N. The post-fire effects on nitrogen are short-lived, usually lasting about a year or so.
Varied responses in post-fire NO3-N stream water concentrations ranging from no significant
change to some increase have been documented in the literature. In some cases, an ammonium

pulse may be observed before the NO3-N pulse. Higher levels of NO3-N in streamflow were
found in watersheds that receive higher levels of atmospheric deposition of nitrogen. In most
cases, streamflow NO3-N values observed were less than 10 mg/L (Neary et. al. 2005b,
MacDonald and Stednick 2003).

Phosphorus complexes with organic compounds in the soil and therefore does not leach as
readily as NO3-N. The literature shows little to no increase in total phosphorus concentrations
after burning. Phosphorus concentrations in overland flow from burned hillslopes can be
increased, but generally not in amounts that would degrade water quality. Phosphorus can be
limiting in aquatic environments and is quickly taken up by aquatic organisms, especially algae
(Neary et. al. 2005b).

There is not a lot of information available about post-fire heavy metal or other nutrient loss in the
literature. Generally, there is a flush of nutrients in the first post-fire streamflow events, and then
concentrations decrease in subsequent events. Losses are insignificant relative to the total capital
of these nutrients. There is some potential for nutrients to be lost due to post-fire erosion but
this is generally only a small fraction of the total nutrient capital on-site and should not normally
be a problem (Neary et. al. 2005b). Volatilization of forest organic matter can result in organic
compounds that may discolor water and cause heavy metals such as iron or manganese to be
released from forest soils. Iron gives water an aesthetically displeasing orange color and
manganese imparts a metallic taste to the water. These effects were observed in Strontia Springs
Reservoir following the Buffalo Creek fire (MacDonald and Stednick 2003). Stream water pH
can be affected by ash deposition immediately after the fire. Increased pH in soils post-fire can
also contribute to increases in stream water pH (Neary et. al. 2005b).

Use of fire retardants for fire suppression can contaminate water supplies if the retardant is
directly applied to a water body. The composition of fire retardants commonly in use is about 85
% water, 10 % inorganic fertilizers (ammonium phosphate or ammonium sulfate) and 5 %
additives such as gum thickeners, coloring agents and corrosion inhibitors. Fire retardants have a
low toxicity for humans but can be toxic to aquatic life including fish. Retardant formulations
that contain the anticorrosive agent sodium ferrocyanide pose greater toxicity to aquatic species
than those formulations without this agent. The Forest Service has not used retardant
formulations that contain sodium ferrocyanide since 2005 and plans to discontinue using these
formulations all together after the 2007 fire season. The ammonium compounds in the retardant
can be toxic to fish but toxicity depends upon exposure time, availability of areas to avoid
contaminated water, water quality including pH, amount of retardant introduced into the water
body and size and type of water body (U.S. Forest Service 2007, Comas 2007).

In 2000, the Forest Service and other fire-fighting partners (U.S. Forest Service et. al. 2000)
established guidelines for the aerial delivery of retardant or foam near waterways. This guidance
requires the avoidance of aerial application of retardant or foam within 300 feet of waterways
unless certain circumstances warrant an exception to this guideline. There were eleven reported
cases of accidental application of retardant to waterways between August 2001 and December
2005, three of which resulting in significant fish kills. Two of these instances involved aerial
application of a retardant formulation containing sodium ferrocyanide. The other instance was a
ground based accidental spill directly in to the creek and the retardant did not contain sodium

ferrocyanide. The 2007 Environmental Assessment for Aerial Application of Fire Retardant
concludes that adherence to the 2000 Guidelines will result in no effect to aquatic environments.
In those cases where a deviation from the Guidelines is necessary, there is a low potential risk to
aquatic environments (U.S. Forest Service 2007, Comas 2007).

Changes to Water Purity – “So What?”

Any disturbance to a forested system will disrupt nutrient cycling and increase the potential for
nutrient losses. Studies have shown that nutrient losses following timber harvest and wildfire are
generally short-lived, small in magnitude compared to the total nutrient capital on-site, and
within drinking water standards. Introduction of other pollutants during treatments or fire
suppression (i.e. pesticides, petroleum products or fire retardant) can be minimized or avoided by
use of Watershed Conservation Practices or other BMPs.

Watershed factors to consider in prioritizing areas for treatment

The areal extent of the MPB epidemic is huge while the resources available to address impacts
on NFS lands is limited. The Forest Service Bark Beetle Incident Implementation Plan 2007 –
2011 proposes projects to reduce wildfire risk to critical watersheds. Watershed factors to
consider in identifying and prioritizing critical watersheds for projects include the following:

      Municipal Watershed/Source Water Area for public water supply systems
      State 303(d) or Monitoring and Evaluation (in Colorado) listing for sediment
      Aquatic TES species
      Watershed condition class rating per Forest Plan
      Watershed Improvement Needs inventory and opportunities


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British Columbia Ministry of Forests and Range. 2004. Recommended operational procedures
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Busse, M.D. and L.F. DeBano. 2005. Chapter 4: Soil Biology. In: Neary, D.G., K.C. Ryan,
L.F. DeBano. eds. 2005. Wildland fire in ecosystems: effects of fire on soils and water. Gen.
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Cheng, J.D. 1989. Streamflow changes after clear-cut logging of a pine beetle infested
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Comas, S. 2007. Aquatics Specialist Report and Biological Evaluation for Aerial Application of
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DeBano, L.F., D.G. Neary, and P.F. Ffolliott. 2005. Chapter 2: Soil Physical Properties. In:
Neary, D.G., K.C. Ryan, L.F. DeBano. eds. 2005. Wildland fire in ecosystems: effects of fire
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    Complete rapid assessment of potential risks and impacts to soil and water resources.
                          Develop strategies to reduce impacts.

Bark Beetle Mortality – Direct and indirect effects of bark beetle tree mortality on soil and water
resources (sort of No Action alternative)
Potential Effects of Wildfire – Rationale is there would be a greater risk of high intensity/high
severity wildfire due to widespread bark beetle tree mortality in the absence of treatments to
reduce fuel loadings. (This hypothesis is currently the subject of much debate in the scientific
community.) There are potential direct and indirect effects of resulting high severity wildfire on
soil and water resources.
Potential Effects of Treatment – Potential effects of treatments to reduce hazardous fuel loading
risk of wildife. These treatments could include thinning, salvage harvest, prescribed fire and
associated transportation system activities and pesticide treatments.
Mitigation Strategies – Actions that could be taken to mitigate direct and indirect effects of bark
beetle tree mortality, and/or potential effects of wildfire or treatment activities, and actions that
could be taken to restore watershed conditions and thereby reduce cumulative effects.

Bark Beetle Mortality

1   Hydrologic Function/Water Yield
    a Direct Effects
       i) Reduced evapotranspiration and snow interception due to widespread tree mortality
            could increase annual water yield
            (1) Most of annual water yield increase is in the spring snowmelt runoff
            (2) Perhaps some increases in later summer to fall low flows
       ii) Potentially an increase in peak flow magnitude
       iii) Timing of peak snowmelt and snowmelt runoff is potentially shifted to earlier in
       iv) Magnitude of effects changes over the years post-epidemic
            (1) Moderate increases in the early post-epidemic years
            (2) Greater effects 5 to 15 years post-epidemic
            (3) Effects persisting at a decreasing rate, possibly up to 60 years
       v) Response depends upon precipitation
            (1) No effects evident in areas with annual precipitation less than 18 to 20 inches
            (2) Larger increases will be seen in wetter years than drier years; very dry years may
                see no increase
       vi) Increase in water yield from bark beetle mortality is probably less than from
            harvesting live trees and likely within the historic range of variation
            (1) Canopy will continue to intercept precipitation until needles are completely gone
            (2) Understory forest, shrub and herbaceous vegetation (especially in mixed species
                subalpine forest stands) will utilize excess water
    b Indirect Effects
       i) Existing roads and ditches concentrate runoff and increase the efficiency of the
            watershed to drain runoff, potentially increasing peak flows over unroaded conditions
       ii) Potential alterations in stream habitat if increases in water yield are beyond capacity
            of stream to assimilate increased flow

    c   Mitigation Strategies
        i) Proper maintenance (clearing…) of roadside ditches to prevent blowouts (WCP 10f,
             WCP 11c)
        ii) Harden drainage structures in 1st and 2nd order drainages to pass greater peak flows
             (WCP 4a, WCP 4d)
        iii) Obliterate unneeded roads to reduce compacted surfaces and restore subsurface flow
             paths to decrease efficiency of watershed to drain runoff and reduce peak flows
             (reduce Connected Disturbed Areas (CDAs) in the watershed) (WCP 1a).

2   Riparian Areas
    a Direct Effects
       i) Increased loading of large wood to stream channels from tree mortality
       ii) Reduced nutrient uptake by riparian overstory may reduce nutrient retention within
            riparian zones and increase nutrient export to surface water
       iii) Increase in light, moisture and nutrients available to riparian understory
    b Indirect Effects
       i) Increased stream temperature from loss of shading due to tree mortality in riparian
       ii) Changes in stream channel dynamics, morphology and sediment transport from
            increases in large woody debris loading
       iii) Fish passage concerns at closed bottom stream crossings where increases in flow and
            velocity can impede passage.
    c Mitigation Strategies
       i) Redesign and improve high risk stream crossings to pass large wood and organic
            debris (?) (WCP 4b)
       ii) Consider design changes to high risk crossing structures at critical sites where fish
            passage could be a concern due to increased flows (WCP 4c)

3 Sediment Production
   a Direct Effects
       i) No direct effects expected because no ground disturbance
   b Indirect Effects
       i) No indirect effects expected because no ground disturbance
   c Mitigation Strategies
       i) No mitigation measures needed for sediment control

4 Soil Quality
   a Direct Effects
       i) Loss of ectomycorrhizal inocula from mortality of overstory lodgepole pine
       ii) Increased availability and export of soil nitrogen due to reduced demand for nutrients
           by dead trees in overstory
   b Indirect Effects
       i) Difficulties in natural regeneration of lodgepole seedlings due to loss of ECM, viable
           seed and limited seedbed access
   c Mitigation Strategies
       i) Reforestation as quickly as possible

       ii) Protection of understory regeneration will enhance on-site nutrient uptake and reduce
           nutrient losses

5 Water Purity
   a Direct Effects
      i) Increased export of nutrients to surface and subsurface waters
   b Indirect Effects
      i) Altered nutrient and water uptake by riparian vegetation as it responds to overstory
   c Mitigation Strategies
      i) Protect residual understory
      ii) Limit degradation or disruption of forest floor or surface mineral soil


1 Hydrologic Function/Water Yield
   a Direct Effects
      i) Greater increases in water yield over just MPB mortality alone
           (1) Removal of trees decreases stand roughness that would have continued to
               intercept precipitation
           (2) Removal of understory vegetation and non-pine trees eliminates
               evapotranspiration from this vegetation
           (3) Additional ground disturbance during harvest operations and site prep changes
               stand scale watershed hydrology
           (4) Greater increases in peak flows
           (5) Earlier timing of snowmelt runoff
           (6) Slash disposal could result in significant snow scour
      ii) Alterations in hillslope hydrology (interruption of subsurface flow paths) in
           construction of new roads and ditches
   b Indirect Effects
      i) Potential alterations in stream habitat if increases in water yield are beyond capacity
           of stream to assimilate increased flow
   c Mitigation Strategies
      i) Maintain/enhance surface roughness (such as using lop and scatter slash treatment) to
           capture and retain moisture (i.e. snow) on-site in harvest units, balanced with need to
           reduce fuel loading. (WCP 1b)
      ii) Plan harvest units at the watershed scale to minimize road density (WCP 9)
      iii) Prompt reforestation of logged areas
      iv) Retain species other than lodgepole pine during logging, as well as small groups
           (>0.2 ha) of dead pine
      v) Increase the size of reserved areas (not harvested), particularly in areas where a large
           proportion of the watershed is to be treated.
      vi) Retain areas with advanced regeneration to serve as a “hydrologic pump” to return
           moisture back to the atmosphere, reduce ECAs and provide a future timber supply

       vii) Construct, inspect and maintain roads to ensure natural surface and shallow
            subsurface drainage remains intact.

2 Riparian Areas
   a Direct Effects
      i) Mechanical disturbance to streambanks reduces streambank stability and increases
           streambank erosion
      ii) Reduction of riparian buffer zones where road right-of-ways intersect stream
   b Indirect Effects
      i) Loss of filtering capacity of riparian buffer strip due to ground disturbance
      ii) Increase in stream temperatures due to loss of shading from removal of overstory
           trees and disturbance of understory vegetation
      iii) Reduction in long-term LWD recruitment due to removal of overstory trees
   c Mitigation Strategies
      i) Ensure that all activities undertaken in the riparian area have the maintenance or
           improvement of stream health and riparian ecosystem condition as the primary
           desired outcome (WCP 3)
      ii) Relocate roads to outside of riparian areas where feasible to restore riparian area
           condition and function
      iii) Ensure at least one-end log suspension in the WIZ. Fell trees in a way that protects
           vegetation in the WIZ from damage (WCP 3d)
      iv) Consider expanding the width of the riparian buffer to mitigate effects of upslope
      v) Use feathering or topping techniques to protect riparian area integrity from
      vi) Develop site layout and harvesting strategies to identify areas where riparian fuel
           loads can be reduced without significantly compromising the integrity of riparian
           buffer zones

3 Sediment Production
  a Direct Effects
      i) Increases in sediment sources with construction, reconstruction and maintenance of
          roads (permanent and temporary), skid trails and landings.
  b Indirect Effects
      i) Reduction of ground cover in harvest areas or prescribed burn units could lead to
          increased erosion.
      ii) Disturbance on steep slopes and sensitive soils could lead to increased erosion.
  c Mitigation Strategies
      i) Reduce Connected Disturbed Areas (CDAs) to minimize sediment transport into
          stream channels and other water bodies
      ii) Use WCPs/BMPs in road construction and maintenance, salvage/harvest and other
          ground disturbing activities to minimize sediment production and off-site transport
          (WCP 9a, WCP 9b, WCP 9c, WCP 9d, WCP 9e, WCP 9f, WCP 9i, WCP 9j, WCP
          10a, WCP 10b, WCP 10c, WCP 10d, WCP 10f, WCP 11a, WCP 11b, WCP 11c, WCP
          11d, WCP 11e, WCP 11f, WCP 11g)

       iii) Do not use ground-based skidding or mechanical treatments on sustained slopes
            greater than 40% (WCP 9g)
       iv) Use winter logging over an adequate snowpack on low gradient slopes to minimize
            ground disturbance
       v) Set up contract clauses that ensure use of low ground disturbing equipment and
            logging systems
       vi) Use WCPs/BMPs during prescribed fires to minimize potential for increased erosion
            and sediment delivery to water bodies.

4 Soil Quality
   a Direct Effects
       i) Increased areas of soil disturbance from skid trails, landings and road construction
   b Indirect Effects
       i) Some increased erosion and hydrophobicity from prescribed fire treatments, but less
            than wildfire
   c Mitigation Strategies
       i) Close and obliterate unneeded roads, skid trails and landings to mitigate detrimental
            soil compaction (WCP 12a)
       ii) Consider winter logging/treatment operations to protect soils (WCP 13b)
       iii) Conduct prescribed fires to minimize residence time on soil while meeting burn
            objectives (WCP 13c)
       iv) Retain logging slash, limit the use of whole tree harvesting
       v) Regulate post-harvest site preparation in order to minimize forest floor disturbance
       vi) Minimize high severity slash pile burning
       vii) Develop and validate soil quality indicators that are robust predictors of long term site

5 Water Purity
   a Direct Effects
      i) Contamination from pesticide drift or stemflow delivery of chemicals from treated
      ii) Contamination from spills of hazardous materials (fuel, pesticide)
   b Indirect Effects
   c Mitigation Strategies
      i) Use buffer strips to protect water courses from pesticide drift. Follow pesticide label
          directions to minimize drift (WCP 17a)
      ii) Develop and implement hazardous spill plans (WCP 15b, WCP 16a, WCP 16e, WCP


1 Hydrologic Function/Water Yield
   a Direct Effects
      i) Decreased infiltration associated with the loss of organic ground cover, soil aggregate
           disruption, surface sealing or water repellency leads to increased runoff and peak
           (1) Greater peak flow increases during high intensity summer precipitation events
      ii) Mortality of the majority of vegetation on site leads to increased runoff (loss of
           interception and ET)
   b Indirect Effects
      i) Increased peak flows potentially scour aquatic habitats and destabilize streambanks
           leading to channel changes (increased channel width and decreased depth)
      ii) Increased peak flows blow out undersized stream crossing structures
   c Mitigation Strategies
      i) Improve undersized stream crossing structures to pass increased peak flows
      ii) Stabilize unstable streambanks, preferably with bioengineering methods, to reduce
           streambank erosion and associated impacts to aquatic habitats
      iii) Post-fire treatments where necessary to detain runoff on the hillslope
      iv) Road treatments to improve road drainage to reduce risk of post-fire road failures

2 Riparian Areas
   a Direct Effects
      i) Greater loss of shading and greater bank instability with complete loss of streamside
      ii) Loss of sediment filtering capacity as ground cover and streamside vegetation are lost
   b Indirect Effects
      i) Instability in upslope areas leading to increases in debris flows, dry ravel or landslides
          that ultimately affect riparian areas
   c Mitigation Strategies
      i) Balance fuel loading with need for LWD in riparian areas to prevent “cooking” of
          riparian areas when the wildfire does come thru
      ii) Proactively restore riparian area structure and function following the fire.

3 Sediment Production
   a Direct Effects
      i) Large increase in erosion and sediment transport in severely burned areas due to loss
           of ground cover
   b Indirect Effects
      i) Increase in bank erosion from increased streamflows increases sediment in channels
      ii) Increase in sediment from blown out stream crossings due to increased peak flows
      iii) Decreased aquatic habitat from sediment filling pools and spawning gravels
   c Mitigation Strategies
      i) Improve and armor undersized stream crossing structures to pass increased peak

       ii) Stabilize unstable streambanks, preferably with bioengineering methods, to reduce
            streambank erosion and associated impacts to aquatic habitats
       iii) Prompt rehabilitation (ground cover and revegetation) of priority areas to limit
            sediment impacts (BAER)

4 Soil Quality
   a Direct Effects
       i) Longer duration and higher fire temperatures from increased fuel loading lead to
            greater soil impacts
       ii) Decreased infiltration from soil hydrophobicity
   b Indirect Effects
       i) Increased erosion from large areas of bare ground due to loss of ground cover
       ii) Loss of nutrients in runoff
       iii) Change in soil physical structure
   c Mitigation Strategies

5 Water Purity
   a Direct Effects
      i) Fire retardant dropped directly into water bodies can have toxic effects to aquatic
   b Indirect Effects
      i) Nutrient enrichment from runoff of ash and sediment
      ii) Contamination (mercury, for example) from runoff
   c Mitigation Strategies
      i) Follow the 2000 Guidelines for Aerial Delivery of Fire Retardant or Foam near
           Waterways (U.S. Forest Service et. al. 2000) to avoid dropping fire retardant directly
           into streams or other water bodies.
      ii) Maintain streamside buffers strips where possible, especially in prescribed burning
           operations, to capture sediment and nutrients from burned upslope areas.

APPENDIX A -- WCPs for Bark Beetle Projects


WCP 1 – Manage land treatments to conserve site moisture and to protect long-term
stream health from damage by increased runoff

a. In each watershed containing a 3rd order and larger stream, limit connected disturbed areas so
that the total stream network is not expanded by more than 10%. Progress toward zero
connected disturbed area as much as practicable. Where it is impossible or impracticable to
disconnect a particular connected disturbed area, minimize the areal extent of the individual
connected disturbed area as much as practicable. In watersheds that contain stream reaches in
diminished stream health class, allow only those actions that will maintain or reduce watershed-
scale Connected Disturbed Area.

b. Design the size, orientation, and surface roughness (that is, slash and other features that would
trap and hold snow on site) of forest openings to prevent snow scour and site desiccation.

WCP 2 – Manage land treatments to maintain enough organic ground cover in each
activity area to prevent harmful increased runoff.

a. Maintain the organic ground cover of each activity area so that pedestals, rills, and surface
runoff from the activity area are not increased. The amount of organic ground cover needed will
vary by different ecological types and should be commensurate with the potential of the site.


WCP 3 – In the water influence zone next to perennial and intermittent streams, lakes, and
wetlands, allow only those actions that maintain or improve long-term stream health and
riparian ecosystem condition.

a. Allow no action that will cause long-term change to a lower stream health class in any stream
reach. In degraded systems (that is At-risk or Diminished stream health class), progress toward
robust stream health with the next plan period.

b. Allow no action that will cause long-term change away from desired condition in any riparian
or wetland vegetation community. Consider management of stream temperature and large
woody debris recruitment when determining desired vegetation community. In degraded
systems, progress toward desired condition within the next plan period.

c. Keep heavy equipment out of streams, swales and lakes, except to cross at designated points,
build crossings, or do restoration work, or if protected by at least 1 foot of packed snow or 2
inches of frozen soil. Keep heavy equipment out of streams during fish spawning, incubation,
and emergence periods.

d. Ensure at least one-end log suspension in the WIZ. Fell trees in a way that protects
vegetation in the WIZ from damage. Keep log landings and skid trails out of the WIZ, including

m. Do not excavate earth material from, or store excavated earth material in, any stream, swale,
lake, wetland or WIZ.

WCP 4 – Design and construct all stream crossings and other instream structures to
provide for passage of flow and sediment, withstand expected flood flows, and allow free
movement of resident aquatic life.

a. Install stream crossings to meet Corps of Engineers and State permits, pass normal flows, and
be armored to withstand design flows.

b. Size culverts and bridges to pass debris. Engineers work with hydrologists and aquatic
biologists on site design.

c. Install stream crossings on straight and resilient stream reaches, as perpendicular to flow as
practicable, and to provide passage of fish and other aquatic life.

d. Install stream crossings to sustain bankfull dimensions of width, depth and slope and keep
streambeds and banks resilient. Favor bridges, bottomless arches or buried pipe-arches for those
streams with identifiable flood plains and elevated road prisms, instead of pipe culverts. Favor
armored fords for those streams where vehicle traffic is either seasonal or temporary, or the ford
design maintains the channel pattern, profile and dimension.

e. Install or maintain fish migration barriers only if needed to protect endangered, threatened,
sensitive, or unique native aquatic populations, and only where natural barriers do not exist.

WCP 5 – Conduct actions so that stream pattern, geometry, and habitats maintain or
improve long-term stream health.

a. Add or remove rocks, wood or other material in streams or lakes only if such action maintains
or improves stream and lake health. Leave rocks and portions of wood that are embedded in
beds and banks to prevent channel scour and maintain natural habitat complexity.

WCP 6 – Maintain long-term ground cover, soil structure, water budgets, and flow
patterns of wetlands to sustain their ecological function.

a. Keep ground vehicles out of wetlands unless protected by at least 1 feet of packed snow or 2
inches of frozen soil. Do not disrupt water supply or drainage patterns into wetlands.

b. Keep roads and trails out of wetlands unless there is no other practicable alternative. If roads
and trails must enter wetlands, use bridges or raised prisms with diffuse drainage to sustain flow
patterns. Set crossing bottoms at natural levels of channel beds and wet meadow surfaces.
Avoid actions that may dewater or reduce water budgets in wetlands.

f. Do not build firelines in or around wetlands unless needed to protect life, property, or
wetlands. Use hand lines with minimum feasible soil disturbance. Use wetland features as
firelines if practicable.


WCP 9 – Limit roads and other disturbed areas to the minimum feasible number, width,
and total length consistent with the purpose of specific operations, local topography and

a. Construct roads on ridge tops, stable upper slopes or wide valley terraces if practicable.
Stabilize soils onsite. End-haul soil if full-bench construction is used. Avoid slopes steeper than

b. Avoid soil-disturbing actions during periods of heavy rain or wet soils. Apply travel
restrictions to protect soil and water.

c. Install cross drains to disperse runoff into filter strips and minimize connected disturbed areas.
Make cuts, fills and road surfaces strongly resistant to erosion between each stream crossing and
at least the nearest cross drain. Revegetate using certified local native plants as practicable;
avoid persistent or invasive exotic plants.

d. Construct roads where practicable, with outslope and rolling grades instead of ditches and

e. Retain stabilizing vegetation on unstable soils. Avoid new roads or heavy equipment use on
unstable or highly erodible soils.

f. Use existing roads unless other options will produce less long-term sediment. Reconstruct for
long-term soil and drainage stability.

g. Avoid ground skidding on sustained slopes steeper than 40% and on moderate to severely
burned sustained slopes greater than 30%. Conduct logging to disperse runoff as practicable.

i. During and following operations on outsloped roads, retain drainage and remove berms on the
outside edge except those intentionally constructed for protection of road grade fills.

j. Locate and construct log landings in such a way to minimize the amount of excavation needed
and to reduce the potential for soil erosion. Design landings to have proper drainage. After use,
treat landings to disperse runoff and prevent surface erosion and encourage revegetation.

WCP 10 – Construct roads and other disturbed sites to minimize sediment discharge into
streams, lakes and wetlands.

a. Design all roads, trails and other soil disturbances to the minimum standard for their use and
to “roll” with the terrain as feasible.

b. Use filter strips, and sediment traps if needed, to keep all sand-sized sediment on the land and
disconnect disturbed soil from streams, lakes, and wetlands. Disperse runoff into filter strips.

c. Key sediment traps into the ground. Clean them out when 50% full. Remove sediment to a
stable, gentle, upland site and revegetate.

d. Keep heavy equipment out of filter strips except to do restoration work or build armored
stream or lake approaches. Yard logs up out of each filter strip with minimum disturbance of
ground cover.

e. Build firelines outside filter strips unless tied to a stream, lake, or wetland as a firebreak with
minimal disturbed soil. Retain organic ground cover in filter strips during prescribed fires.

f. Design road ditches and cross drains to limit flow to ditch capacity and prevent ditch erosion
and failure.

WCP 11 – Stabilize and maintain roads and other disturbed sites during and after
construction to control erosion.

a. Do not encroach fills or introduce soil into streams, swales, lakes or wetlands.

b. Properly compact fills and keep woody debris out of them. Revegetate cuts and fills upon
final shaping to restore ground cover, using certified local native plants as practicable; avoid
persistent or invasive exotic plants. Provide sediment control until erosion control is permanent.

c. Do not disturb ditches during maintenance unless needed to restore drainage capacity or repair
damage. Do not undercut the cut slope.

d. Space cross drains according to road grade and soil type as indicated below (exhibit 01). Do
not divert water from one stream to another.

e. Empty cross drains onto stable slopes that disperse runoff into filter strips. On soils that may
gully, armor outlets to disperse runoff. Tighten cross-drain spacing so gullies are not created.

f. Armor rolling dips as needed to prevent rutting damage to the function of the rolling dips.
Ensure that road maintenance provides stable surfaces and drainage.

g. Where berms must be used, construct and maintain them to protect the road surface, drainage
features, and slope integrity while also providing user safety.

h. Build firelines with rolling grades and minimum downhill convergence. Outslope or
backblade, permanently drain, and revegetate firelines immediately after the burn. Use certified
local native plants as practicable; avoid persistent or invasive exotic plants.

WCP 12 – Reclaim roads and other disturbed sites when use ends, as needed, to prevent
resource damage.

a. Site-prepare, drain, decompact, revegetate, and close temporary and intermittent use roads and
other disturbed sites within one year after use ends. Provide stable drainage that disperses runoff
into filter strips and maintains stable fills. Do this work concurrently. Stockpile topsoil where
practicable to be used in site restoration. Use certified local native plants as practicable; avoid
persistent or invasive exotic plants.

b. Remove all temporary stream crossings (including all fill material in the active channel),
restore channel geometry, and revegetate the channel banks using certified local native plants as
practicable; avoid persistent or invasive exotic plants.

c. Restore cuts and fills to the original slope contours where practicable and as opportunities
arise to re-establish subsurface pathways. Use certified local native plants as practicable; avoid
persistent or invasive exotic plants. Obtain stormwater (402) discharge permits as required.

d. Establish effective ground cover on disturbed sites to prevent accelerated on-site soil loss and
sediment delivery to streams. Restore ground cover using certified native plants as practicable to
meet revegetation objectives. Avoid persistent or invasive exotic plants.


WCP 13 – Manage land treatments to limit the sum of severely burned soil and
detrimentally compacted, eroded, and displaced soil to no more than 15% of any activity

a. Restrict roads, landings, skid trails, and concentrated-use sites, and similar soil disturbances to
designated sites.

b. Operate heavy equipment for land treatments only when soil moisture is below the plastic
limit, or protected by at least 1 foot of packed snow or 2 inches of frozen soil.

c. Conduct prescribed fires to minimize the residence time on the soil while meeting the burn
objectives. This is usually done when the soil and duff are moist.

WCP 14 – Maintain or improve long-term levels of organic matter and nutrients on all

a. On soils with surface soil (A-horizon) thinner than 1 inch, topsoil organic matter less than 2%,
or effective rooting depth less than 15 inches, retain 80 – 90 % of the fine (less than 3 inches in

diameter) post treatment logging slash in the stand after each clearcut and seed-tree harvest.
Consider need for retention of coarse woody debris slash in each activity area to balance soil
quality requirements and fuel loading concerns.

b. If machine piling of slash is done, conduct piling to leave topsoil in place and to avoid
displacing soil into piles or windrows.


WCP 15 – Place new sources of chemical and pathogenic pollutants where such pollutants
will not reach surface or ground water.

b. Locate vehicle service and fuel areas, chemical storage and use areas, and waste dumps and
areas on gentle upland sites. Mix, load, and clean on gentle upland sites. Dispose of chemicals
and containers in State-certified disposal areas.

c. Locate temporary labor, spike, logging and fire camps such that surface and subsurface water
resources are protected. Consideration should be given to disposal of human waste, wastewater
and garbage and other solid wastes.

WCP 16 – Apply runoff controls to disconnect new pollutant sources from surface and
ground water.

a. Install contour berms and trenches around vehicle service and refueling areas, chemical
storage and use areas, and waste dumps to fully contain spills. Use liners as needed to prevent
seepage to ground water. Prepare Spill Prevention Control and Countermeasure Plan per the
requirements of 40 CFR 112.

e. Inspect equipment used for transportation, storage or application of chemicals daily during
use period for leaks. If leaks or spills occur, report them and install emergency traps to contain
them and clean them up. Refer to FSH 6709.11, chapter 60 for direction on working with
hazardous materials.

f. Report spills and take appropriate clean-up action in accordance with applicable state and
federal laws, rules and regulations. Contaminated soil and other material shall be removed from
NFS lands and disposed of in a manner according to state and federal laws, rules and regulations.

WCP 17 – Apply chemicals using methods that minimize risk of entry to surface and
ground water.

a. Favor pesticides with half-lives of 3 months or less when practicable to achieve treatment
objectives. Apply at lowest effective rates as large droplets or pellets. Follow the label
directions. Favor selective treatment. Use only aquatic-labeled chemicals in the WIZ.

APPENDIX B – Comparative Summary of toxicological effects of pesticides used on MPB

      Pesticide                     Carbaryl                      Permethrin                    Bifenthrin***
                                                                                          known as a restricted use
                                                                                        pesticide because of its toxicity
                                                                                           to fish and other aquatic
                                                            acts by interfering with
                         disrupts the nervous systems       transmission of nerve
   Mode of Action                                                                           similar to permethrin
                              of humans and other             impusles along the
                                   vertebrates                     neurons
   Acute toxicity to:
  humans/mammals                moderate toxicity              low to moderate                moderately toxic
    ~ by inhalation        practically non-toxic to rats    N/A should be avoided                  N/A
    ~ by ingestion           low to moderate toxicity       N/A should be avoided             moderately toxic
      ~ thru skin        low in toxicity when applied to      no toxicity observed      skin irritation, low in toxicity
                                 rats and rabbits
                          although it may cause minor
                         skin and eye irritation, it does                               no information available but
                          not appear to be a significant                                the fate in humans and other
                         chronic health risk at or below      long term feeding of
                                                                                           mammals is: it is rapidly
                            occupational levels. Male        pyrethroids resulted in
   chronic toxicity                                                                      broken down and excreted.
                          volunteers who ingested low       an increase in liver size
                                                                                         What was not broken down
                           doses for six weeks did not      and excessive formation
                                                                                          completely accumulated in
                            show symptoms, but tests                                    tissues with high fat content.
                           indicated slight changes in
                                 body chemistry
                             moderately toxic to trout                                        extremely toxic,
          fish                                                  extremely toxic
                                     species.                                              bioaccumulates in fish
                                                                                            extremely toxic, can
     amphibians                                                 extremely toxic
                                      N/A                                                      bioaccumulate
                                                              highly toxic to honey
                                                              bees, moderately to          extremely toxic to most
  insects (non-target
                           highly toxic to honey bees,       highly toxic to aquatic      insects, including honey
                         freshwater invertebrates, and      insects at relatively low                bees
                               macroinvertebrates                     levels

         birds                                                practically non-toxic         slightly toxic to birds

                                                             pH 9 at 20 half-life is    unknown; stable hydrolosis
  hydrolosis half-life    distilled water: 3.2 hours at            242 days                        (?)
                         pH 9 and 12.1 days at pH 7.
                          sandy loam soil: 4-17 days;         anaerobic soil: 197
                          clay loam soil: 21-27 days,                                   anaerobic soil: 97-156 days;
     soil half-life                                            days; aerobic soil
                           and 78 days for anaerobic                                     aerobic soil: 65-125 days
                                                              average 39.5 days
  Suspected (EPA):                carcinogen                      carcinogen                    carcinogen
                            cardiovascular toxicant           endocrine toxicant                neurotoxin
                            developmental toxicant          gastrointestinal toxicant   *** OVERALL VERY LITTLE
                                 neurotoxicant                   neurotoxicant          COMPLETE INFORMATION
                            gastrointestinal toxicant        reproductive toxicant           ON BIFENTHRIN


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