Upper Ocklawaha River Basin Working Group by mjg44600

VIEWS: 18 PAGES: 12

									                                            DRAFT
                              Statewide Stormwater Treatment Rule
                                 Technical Advisory Committee
                                       Meeting Highlights
                                         March 5, 2008

                                     DEP Bob Martinez Center
                                  2600 Blair Stone Road, Rm. 609
                                         Tallahassee, FL


                                          TAC Attendees

         ENTITY               REPRESENTATIVE        PRESENT         ALTERNATE          PRESENT
         Audubon                   Paul Gray              X          Eric Draper
       1000 Friends             Charles Pattison                   Dan Pennington         X
    SWF Conservancy            Andrew McElwaine           X        Jennifer Hecker
   Florida Homebuilders
                                 David Carter             X        Dikran Kalaydjian      X
        Association
                                 Bob Higgins              X          Rick Creech
Florida Engineering Society
                                 Rick Barber              X          Bob Howard
      Florida Chamber            Doug Durbin              X        Chuck Littlejohn
  Florida League of Cities        John Buss               X         Sam Amerson
   Florida Association of
                                 Kim Ornberg              X          Lori Cunniff
           Counties
Florida Local Environmental
                                 Jack Merriam             X        Lenny Vialpando        X
     Resource Agencies
     Florida Stormwater
                                 Chuck Walter             X        Don Donaldson          X
         Association
            FDOT                 Josh Boan                X          Rick Renna           X
   Urban Redevelopment         Grady Pridgeon                       Steven Kurcan         X
      Urban Mixed Use            Bill Murray
            DACS                 Bill Bartnick            X          Rich Budell
     South Florida area           Alan Hall               X
       NE Florida area          Neil Aikenhead            X
    Central Florida area       Devo Seereeram             X        Charmaine Saith        X
       Reuse Utilities          Todd Swingle              X
 Apalachicola Riverkeeper        Andy Smith               X         Dan Tonsmeir

   Agenda Items:
      • Welcome/ Introductions
      • Sunshine Law (Meredith Fields)
      • New Stormwater Rule – Why? (Eric Livingston)
      • New Stormwater Rule – How? (Harvey Harper)
      • Lunch
      • Issue Papers
             o Karst Sensitive / Ground Water Protection (Paul O’Neil)
             o Wet Detention Ponds (Cammie Dewey)
             o Wetlands for Stormwater Treatment (Eric Livingston)
             o Low Impact Development BMPs (Eric Livingston)
             o Altered Hydrology/ Legacy Pollutants (Damon Meiers)
             o Urban Redevelopment (Damon Meiers)
             o Size Threshold (Eric Livingston)


   SSTR TAC 3-5-08                              1
                                         DRAFT
   •   New Stormwater Rule – Strawman Handbook (Michael Bateman)
   •   Next Steps


Highlights:

   Welcome/ Introductions and Housekeeping (Eric Livingston, Kathy Harrigan)
   • This TAC is an advisory committee. The intent is to get consensus on as many items as
      possible and recommend those consensus items to DEP for their consideration in going
      forward with the rule-making process. There will not be any formal votes as the TAC
      itself is not a decision-making group.
   Sunshine Law Primer (Meredith Fields [Meredith.C.Fields@dep.state.fl.us])
   • Government in the Sunshine (Florida Statutes286.011/ Article I, S.24(b) Florida
      Constitution) – applicable to any gathering of 2 or more members of the TAC to discuss
      some matter that would foreseeably come before the board for action. The TAC
      members may not discuss in person (including casual “hallway” discussion), e-mail,
      telephone conversations, etc. any topics relating to this TAC outside of these publicly
      noticed meetings.
   • Alternates may speak with their primary TAC counterpart outside of the publicly noticed
      meeting and not be in violation of the Sunshine Law; however, the alternate is treated
      like a primary member of the TAC and must follow all the same communication
      restrictions.
   • Sub-groups of the TAC are not subject to the Sunshine Law if they are only fact-finding
      or prioritizing recommendations. If they are making recommendations to the main
      committee or narrowing the scope of options, then the sub-group meetings are subject to
      Sunshine.
   • Even during a break/ recess in a public meeting, TAC members may be violating the
      Sunshine Law if they speak to each other in a manner not generally audible to the public
      attending the meeting.
   • If TAC members serve on other boards together, they may meet to discuss duties as
      part of the other board; however, if those duties/ discussions relate to matters that will
      foreseeably come before the TAC, it is a violation of the Sunshine Law.
   • The TAC meetings are not required to be audio taped; however, if they are, then the
      tape is part of the public record.
   • Knowing violation of the Sunshine Law is a second degree misdemeanor.
   • Any e-mail communication that a TAC member wants to have with other members
      should be sent first to Kathy Harrigan (Kathleen.Harrigan@dep.state.fl.us). She will
      appropriately distribute the information in conformance with the Sunshine Law.
   New Stormwater Rule – Why? (Eric Livingston [Eric.Livingston@dep.state.fl.us])
   • Human presence in a watershed causes changes in the land characteristics and results
      in decreased recharge, increased speed and volume of runoff, and increased pollutants.
   • Florida was the first state in the country requiring treatment of stormwater from new
      development. The original statewide stormwater rule, Chapter 17-25, F.A.C., became
      effective in 1982 (following an interim regulation Ch. 17-4.248, F.A.C. effective in 1979)
      and set the performance standard to 80% average annual load reduction of TSS (80%
      was chosen to be equitable between point and non-point reduction requirements and
      because 80% reduction is the threshold where the costs begin to increase to achieve
      additional reduction). Originally the Department implemented the rule; however, it was
      delegated to each of the Water Management Districts (except NW Florida WMD) in the
      mid 1980’s.


SSTR TAC 3-5-08                            2
                                          DRAFT
   •   In 1990, the State Water Implementation Rule (Chapter 62-40, F.A.C.) was adopted and
       the institutional foundation (DEP, WMD, and local govt’s), goals (control quantity as well
       as quality), and performance standards (for new as well as existing discharges) were
       set. The treatment performance standard was revised to read 80% average annual load
       reduction of pollutants that cause or contribute to violations of water quality standards
       (and not only for TSS as in the 1982 performance standards).
   •   Best Management Practices (BMPs) are control techniques used for a given set of
       conditions to achieve water quality and quantity enhancement at a minimum price.
       Effective BMPs vary depending on what part of the state they are used in and include
       structural (for mitigation of pollutants including swales, retention and detention systems,
       wetlands, green roofs, etc.) and non-structural (for prevention of pollutants) practices.
       Treatment efficiency data (including removal efficiencies for TN, TP, TSS, and BOD) for
       various types of structural BMPs was collected over many years and maintained in a
       database.
   •   In determining BMP design criteria to meet a desired performance standard, land use,
       precipitation, BMP efficiency, and pollutant information need to be considered. The
       Design Criteria have been dynamic throughout the different rules and their modifications
       since 1979, and are due for another update.
   •   Phosphorous levels in Florida waters began to decrease after implementing the 1982
       Stormwater Rule and no-discharge policy from point-sources. Since about 2000, [P] has
       begun to increase again because of cumulative effects of discharges from non-point
       sources. 1300 water bodies have been verified as impaired, mostly from nutrients,
       oxygen demanding substances, and bacteria, the sources of which are stormwater from
       existing development, future development, and agricultural land, as well as leachate
       from agricultural lands, landscaping, etc.
   •   We need to have higher levels of stormwater treatment because there are verified
       nutrient impaired waters, elevated nitrates in springs, harmful algal blooms, continuing
       high growth (development) rates, and other incentives such as the Lake Okeechobee
       Protection Act and the LOER (Lake Okeechobee and Estuary Recovery) Initiative.
   •   There is a focus on reducing nutrient loading through things such as the turf grass
       research project, passive nutrient septic tank project, Florida Friendly landscaping
       program, Green Industry BMP program, creating a model landscape ordinance,
       implementing irrigation standards, creating the Golf Course BMP Manual, developing the
       urban fertilizer labeling rule, implementing ag/ urban nutrient management BMPs, and
       now the development of a unified stormwater treatment rule (where post ≤ natural
       conditions).
   •   The Florida erosion and sediment control standards and specs, BMP Manual, and
       Inspector Manual are being revised and updated. Information on erosion and sediment
       control (the designer and reviewer manual) can be downloaded from the UCF
       Stormwater Management Academy website (www.stormwater.ucf.edu). The BMP
       revisions will be integrated into the new statewide stormwater rule and into the NPDES
       stormwater rules.
   •   For the development of the new statewide stormwater treatment rule, Harvey Harper
       was hired by DEP to review the current BMP design criteria, to update Florida’s
       stormwater EMC data, update/ analyze Florida rainfall data, estimate predevelopment
       hydrology and stormwater loadings, update Florida’s BMP effectiveness data, model
       BMP treatment effectiveness, and evaluate BMP design criteria changes needed to
       achieve 80%, 95%, and no net increase in nutrient loads.




SSTR TAC 3-5-08                             3
                                          DRAFT
   •   DEP and the TAC will work together at these workshops for the next 6 months (until
       September or October 2008), Rule workshops will be held from October 2008 through
       February 2009, the Rule will be adopted by May 2009, and effective by July 2009.
   Janet Llewellyn welcomes the TAC and voices DEP’s commitment to the development of
   this rule.
   New Stormwater Rule – How? (Harvey Harper)
   • Three years ago he began evaluating the performance of the current stormwater
       management techniques in Florida (for nitrogen and phosphorous) to see if they met the
       Ch. 62-40 F.A.C. objectives, and if not, to determine how to improve them. He also
       looked at what the design criteria have to be to achieve Pre ≤ Post conditions. The
       study did not include evaluating alternative methods (LID, reuse, street sweeping, etc.)
       or wetland loadings.
   • He began by looking at rainfall data (for 160 sites around the state from 1971 – 2000,
       and some outside the state to generate contours) and saw that it is highly variable (from
       ~38 – 66 in/yr). He looked at the characteristics of rain events from various cities and
       saw that the size of rain events in the keys were generally <1” while the panhandle had
       a larger number of large rain events (there was also a variability of the inter-event dry
       period).
   • He ran a continuous rainfall simulation for a hypothetical 1 acre site (20-25 sites/ region)
       using different combinations of soil types and impervious areas (generally 50+ years of
       data for each site) using the SCS method. Defined two parameters – DCIA and CN.
       The total runoff depth was compared with the rainfall depth to calculate the runoff
       coefficient (C Value Table in Appendix C). He identified 5 similar meteorological zones
       within the state (the area within each zone has statistically similar runoff generation
       potential – dependant on rainfall distribution rather than annual rainfall).
   • To get information on runoff characteristics, he used his 1994 “Stormwater Loading Rate
       Parameters for Central and South Florida” for common land use categories (both pre-
       development and post-development) supplemented with new data for single-family
       residential, high-density residential, low-intensity commercial, highway/ transportation,
       industrial, citrus agriculture, row-crop agriculture, and open space/ forest (ERD is
       currently monitoring stormwater at 22 natural sites in State parks around Florida – have
       collected data for 8 months already and will collect for 4 more before compiling data).
   • The summary of literature-based runoff concentrations in Florida shows that the
       concentration of N and P are both elevated for the more developed land use categories.
   • To achieve no net increase in loadings, efficiencies of 60-95% may be necessary, and
       currently only dry retention and wet detention stormwater management systems are
       capable of that. (Dry detention and filter systems have highly variable removal
       efficiencies and are not being considered under the new rule.)
   • Calculated the performance efficiency of retention practices (using a continuous
       simulation of inputs into a theoretical dry retention pond based on the entire available
       rainfall record for all stations in the region) and assumed 100% removal from all rain
       events with a runoff volume less than the treatment volume – did not consider migration
       through soil. A hypothetical draw-down curve is used to evacuate the water from the
       pond (half in 24 hrs., all in 72 hrs.) Comment: He presumed that the infiltration rates
       required in the rule were achievable, which may not be true. He also assumed that there
       was no ‘first flush’ effect occurring from watershed areas discharging to the pond.
       Clarification: ‘Watershed’ means the area that drains to the pond.
   • A series of tables for each of the 5 zones (in Appendix D) shows the modeled dry
       retention removal efficiencies (accounting for differences in project characteristics). You
       can use the tables to iterate how much retention is required to achieve a particular



SSTR TAC 3-5-08                             4
                                          DRAFT
       removal efficiency. Clarification: We are not heading to 100% removal, only pre vs. post.
       Currently the goal is 80% and we are not even meeting that. Every project currently built
       increases loading above what it was. Pre-development is defined as the natural
       condition. Question: There are no wet retention systems listed. It is possible for a wet
       retention system to work? A: You would have to demonstrate that it does. Question:
       There was an assumption for dry treatment efficiencies of 50% in 24 hrs and 100% in 72
       hrs. What if you can recover 100% in 24 hours? Can credit be given for this? A: If you
       can demonstrate that is the case, then consideration will be given. There is a concern
       about infiltrating water too fast. It must be slow enough to incorporate the pollutant mass
       into the soil, not just pass through the soil and go somewhere else. The 100% treatment
       assumption will be further addressed.
   •   Wet detention is basically a man-made lake, and the removal process occurs within the
       permanent pool. The longer the detention time, the more removal is achieved. The P
       removal curve levels off after about 100 days detention. N removal is never more than
       about 40%. It is commonly used as the fill removed can be used to build-up the lots on-
       site. Question: What is the littoral zone uptake? A: There is a workgroup formed as a
       function of this TAC to look at that. Question: Was this information based on new ponds
       or older ponds that may have organic material build-up on the bottom? A: The data
       points came from existing ponds, so some of them may have been functioning for a
       while and may reflect ‘older pond’ efficiencies.
   •   In wet detention ponds, the upper stratum is aerobic and has the maximum pollutant
       removal. An anoxic layer may form at the bottom, depending on the algal growth (P and
       ammonia is released there). He developed equation to determine anoxic depth in wet
       detention ponds. Comment: If the pond is mixed up (from wind, etc.) could the pollutant
       concentrations increase? A: he has been monitoring ponds for 20 years and has never
       observed that. Question (staff): Even in the 2004 hurricane season, he didn’t observe
       mixing? A:No, but he did observe changes later on from all the additional influx to the
       ponds. Comment (Jack): When aeration systems are installed, there will be mixing.
   •   He developed loading rates for undeveloped natural areas by region and different soil
       types (estimated the load by soil type). Under post-development, the project can’t
       exceed the levels shown. Question (John B.): This does not include the P bound in the
       soil? A: No, only that which was found in the runoff. Comment: Erosion will increase the
       P concentration, not only the human impact.
   •   Conclusion: One removal efficiency (80%) for TN and TP is not appropriate, as you
       would over treat for N and under treat for P. If set for 95%, would over treat for TN and
       in many cases also over treat for TP. It makes sense to set the required removal based
       on Pre-development vs. post development and make it site-specific (the % increase
       between pre and post is the level of treatment that you would need). Comment: We put
       too much emphasis on the 80% and 95% removal numbers from 62-40, as they were
       just ‘best guesses’ back then
   •   [A specific example scenario was worked through with the TAC].
   •   Question: How far away are we from having software ‘plug-and-play version? A: Not
       sure for this model. Devo noted that his company has a program that will be released
       next week and is user friendly. Comment (John B): This seems to be a good approach,
       but there are a lot of assumptions used and they only looked at 30 years of rainfall data.
       Many of the boxes in the tables are not feasible. A: 30 years of rainfall data was used
       for each cell, but for the continuous simulations, used all the rainfall data (~100 years).
   •   Comment (John B.): Ponds in the panhandle do not recover within 72 hours. A state-
       wide rule will be hard to do.




SSTR TAC 3-5-08                             5
                                         DRAFT
   •   Question (staff): If you have decreased concentrations at a depth of ~15-20 feet, should
       you try to dig deeper? A: You should dig the pond as deep as you can, as they collect
       more solids, prevent cattails from growing, and more depth dilutes the effects of
       increasing flows.
   •   Question (John B.): Is this strictly a proposal? What if you are developing on previous
       ag. land which had an even higher concentration of P and N loading than the
       development will have. Defining Pre as ‘natural conditions’ will penalize the
       development, which is decreasing the loading. Need to give some kind of credit to
       compensate for this. Comment (staff): You need to analyze each pond (and it’s mini
       watershed) on it’s own, as the residual loading will move through the site pond by pond.
       Comment (Kim): You are looking at the efficiencies like a ‘ treatment train’.
   •   Question (Neil): Some projects can be designed with just wet detention then (reuse
       pond, low impervious area sites)? A: Possibly. Comment (Devo): His staff have not
       found any scenarios where just using wet detention will work.
   •   Comment (Eric L.): Harvey presented a methodology and data that we can use going
       forward, not the new rule itself. The new rule will encompass other BMPs as well (such
       as reuse and LID).\
   •   Question (John B.): Using the annual rainfall treatment on an annual load basis, the
       runoff might be higher than that coefficient. Individual events may exceed pond
       capacity. Won’t have treatment volume for the big storms. A: Correct. The numbers
       represent the average annual rainfall characteristics over 60 – 100 years, and are not
       representative of any one year. They represent the long term average. Question (John
       B.): Have you thought about separating treatment off-line for flood control? A: Yes, we
       will look into that. Remember that you will still have to meet the WMD requirements on
       top of this.

Lunch Break

   Issue Papers – General: The issue papers were generated by staff (DEP and WMD), who
   are not members of the TAC. Conversations with/ among staff are permissible under
   Sunshine Law.
   Issue Paper: Karst Sensitive / Ground Water Protection (Paul O’Neil)
   • Sensitive Karst Areas (SKA) are areas that have higher potential to contaminate the
       aquifer from stormwater or other surface pollutant sources.
           o How to delineate SKAs? By soil type? By Depth of Floridan Aquifer? By sinkhole
               density (we would use variable criteria based on density)? The graph of
               hydrologic soil groups shows that Type A soils have a higher likelihood of
               groundwater contamination through karst (and dry retention treatment is suitable
               in A soils).
           o If we use a map to identify SKAs, what type of geo-tech data would be needed
               for projects within the SKAs? Should additional permit conditions be required for
               projects in SKAs?
           o Should there be specified subsurface investigation techniques (borings, ground
               penetrating radar, gravity measurements, etc.)?
           o Should we go with a pre-emptive approach or a reactive approach? Pre-emptive
               would be aimed at construction and design standards (example: limiting the
               depth of a pond, ensure a minimum of 3 feet unconsolidated overburden above
               any limestone bedrock encountered during construction, stabilizing sides and
               bottoms of ponds, etc.) Reactive would focus on karst-related failures (example:
               add new specific conditions for permit reviewers that clarify a remedial response



SSTR TAC 3-5-08                            6
                                           DRAFT
               to karst-related failure in a management system and require increased inspection
               and reporting on possible karst-related activity.
            o Should we specify the overburden characteristics (what type and amount of
               material)?
            o How should we address plumes from groundwater contamination sites? Should
               we delineate the plume areas? (We only have dots identifying the sites from
               EPA – no plume data.) Note: In SW Florida, there are 16 Superfund sites within
               16 counties.
            o Question (John B): Have we correlated the data with the Aquatic Vulnerability
               Study (AVA Study) (which was a study completed several years ago)? A: There
               have not been any conclusions drawn from that study yet.
            o Comment (John B.): In Leon County, they mapped the parameters against
               known sites (using depth of overburden, hydraulic conductivity, and sinkhole
               density) and found that a large part of the county was sensitive for karst.
            o Comment: SJRWMD developed a map of SKAs (with the depth of overburden,
               etc.) in 1991. NWFWMD defines SKAs as 100 ft. to overburden. Dr. Wannalista
               is looking at this in Marion County. We don’t want the use of retention basins to
               cause pollution of the aquifer. Dr. Harper is looking at how pollutants move from
               retention basins and how we can mitigate that. Also investigating creation of a
               soil amendment media to minimize pollutant movement in drainfields and in
               green roofs.
            o Question (public): Is there a map showing the likelihood of sinkholes? A: There
               are many maps all using different variables. The question is which variables we
               should use.
            o Comment (Devo): There is a whole body of information about SKAs. If a karst-
               related failure appears and is fixed appropriately, it does not occur again.
               Therefore it should be a reactive approach. We need to look at the the water
               table depth relative to the aquifer. If they are close, there is a high potential for
               sinkhole formation.
            o Paul will make certain that the TAC has access to the applicable WMD studies.
               (DEP will post them on the stormwater rule web site).
            o Question (Paul): Do sinkholes play a significant role in aquifer recharge? A: Yes
               – millions of gallons.
            o Comment (Devo): In SKAs, recharge to the aquifer occurs through windows, and
               is not uniform across the land.
   Issue Paper: Wet Detention Ponds (Cammie Dewey)
   • Wet detention is used in areas with high ground water table. We need to go through the
       existing data at the WMDs (different design requirements) to develop what removal
       efficiencies are.
            o How can we develop efficiency curves based on residence time incorporating
               depth, avg. wet season rainfall, and avg. annual rainfall?
            o Is it possible to make littoral zones optional if another design feature of the pond
               is improved or a treatment train is used? We need to determine what reductions
               we get from littoral zones. Question (Bill B.): Are wet detention ponds the most
               common stormwater treatment BMP in the state? A: Depends on the area of the
               state – in NW Florida, filter ponds are prevalent.
            o Question (David): Are we looking at whether a littoral zone at the outfall is better
               than spreading it around the whole pond? A: Yes.
            o Comment (Paul): Perhaps we can see if mass balance can be used to determine
               long term design.



SSTR TAC 3-5-08                              7
                                        DRAFT
          o    Comment (Bob): Have we identified data from ponds in limestone areas vs. in
               sandy soil areas? Treatment function varies based on soil type. We should add
               another issue to investigate % removal in relation to the soil type. [Damon has
               this type of data.] Comment (staff): sandy soils remove P but get saturated
               quickly – the removal efficiency is not constant over time. (Cammie) We are
               considering data from older systems too.
           o Comment (JohnB.): The Channeled Apple Snail is a problem for littoral zones, as
               it can eat through the plantings in one season. (Kim) There are some problems
               with the snail in Seminole County, but it is not a major issue.
   Issue Paper: Wetlands for Stormwater Treatment (Eric Livingston)
   • The wetland protection act (in the 1980’s) incorporated wetlands into wastewater and
       stormwater systems (using isolated wetlands). As part of a treatment train, we have
       data that shows that this approach does work.
           o We need to determine:
               • What wetlands can be used?
               • Can it be a stand-alone treatment?
               • Should we use the existing criteria or should it be tweaked?
           o In all cases, we can not do any harm to a wetland because they are considered
               waters of the State.
           o Comment (Dan): Maybe we can investigate created wetland design criteria (and
               not only use natural wetlands). Note: Wetlands are not for flood control – would
               need a bypass during flood conditions.
           o Question (Kim): Aren’t wetlands a pollutant source too? A: Sometimes they are a
               sink, and sometimes they are a source, depending on the time of year.
               Comment: Are they really a source or are they just retaining the pollutants they
               receive from up-stream? They retain organic matter on the bottom and release P
               when it dries out.
           o Question (Bob): What about wetlands used as mitigation? A: Remember that
               stormwater systems are not waters of the State, but wetlands are. We can use
               them as a final polishing step in the treatment train.
   Issue Paper: Low Impact Development BMPs (Eric Livingston)
   • LID focuses on better nonstructural practices to reduce the generation of stormwater or
       reduce the amount of nutrients that get into stormwater. How do we provide credit for
       these items? They have been working on this topic for about 3 years and there are links
       on the DEP website to the UCF stormwater research academy. Early green roof testing
       in Florida was a failure because they used the wrong plants and irrigation is necessary.
       They revised the design to include Florida Native wildflowers and added a cistern and
       are having success.
           o We need to determine:
               • How to quantify the load reductions of LID BMPs?
               • Can we quantify the pollutant load elimination/ reductions for Natural Area
                    Conservation?
               • How can we assure consistent design and construction?
               • How can we assure long-term effectiveness through operation and
                    maintenance (example - through changes in ownership)?
           o Question (Andrew): Can LID BMPs survive hurricanes? A: Yes – the green roof
               in Bonita Bay went through 4 in one year. Green roofs also support energy
               efficiency, as it reduces heat transfer through the roof.
           o Question (John B.): How do we translate LID from the technical to the regulatory
               and assure the long-term O&M?



SSTR TAC 3-5-08                           8
                                           DRAFT
          o    Comment (Dan): Green roofs sequester and retain N and P, keeping it out of the
               ponds and soil. (Marty) N goes into the plant mass in a green roof, but it must be
               maintained.
            o Comment (Chuck): O&M is always going to be an issue here. We need to
               consider designing for increased density to reduce sprawl – there is no O&M
               associated with that.
            o Comment: Local entities need to incorporate these LID requirements into their
               Comp Plans.
            o Comment (Andrew): Everyone always needs an ERP from the WMD to develop.
               Maybe that can somehow be used here as an incentive.
   Issue Paper: Altered Hydrology/ Legacy Pollutants (Damon Meiers)
   • Existing conditions, such as altered hydrology or lowering of ground water levels due to
       construction of regional water management systems or water control districts, have
       impacts on runoff which can affect the method for determining an undeveloped
       condition. Also legacy pollutants in the soil due to previous land use can affect the
       efficiency of treatment systems.
               o We need to determine:
                   • Will we accept the existing hydrology?
                   • How can we determine if a site has legacy pollutants and what should we
                        do differently for these sites? (It was not accounted for in the method
                        outlined this morning.)
                            o Comment (Andrew): Restoring a more natural hydrology helps
                                filter out legacy pollutants – he can share research about that from
                                the Chesapeake Bay area.
                            o Comment (Damon): Maybe we should consider leaving this out of
                                the statewide rule and develop WMD basin-specific rules.
                            o Comment (Bob): Is it reasonable to expect a land-owner to be
                                faced with a pre-man pollutant level if developing land that was
                                previously a vegetable truck farm?
                            o Comment (Paul): From the Buck Island Ranch, [P] was 300-700
                                ppb 20 years after they stopped applying fertilizer. If this parcel is
                                developed, how can they achieve something like 40 ppb?
                            o Comment (Bob): This type of scenario could encourage
                                something like pollutant trading.
                            o Comment (Dan): In upper Kissimmee they are going urban from
                                agricultural. Will filling in the canals and ditches affect the legacy
                                pollutant outflow? A: Not sure what the answer is. At Buck Island,
                                when the water table was restored, there was more P in the
                                outflow.
                            o Comment (Josh): If we go with Pre ≤ Post, then we won’t have to
                                worry about future TMDLs.
                            o Comment (Bill): We should consider limiting the scope to
                                concentrated animal operations. The legacy loading from truck
                                farms is not as high as animal farm loadings.
                            o Comment: Are we moving away from the NRCS soil staining? A:
                                The WMD criteria are not going to change.
                            o Question: Will the new rule change wetland mitigation plans? A:
                                Don’t think so. Those will still be based on function.
   Issue Paper: Urban Redevelopment (Damon Meiers)




SSTR TAC 3-5-08                              9
                                         DRAFT
   •   Separate criteria are necessary for redevelopment of urban areas, as they may not be
       able to meet the full extent of the proposed rule (economically or technically).
       Redevelopment needs to be encouraged, so we do not want this approach to be a
       disincentive.
   • We need to determine:
            o How do we define urban redevelopment?
            o What level of treatment should be required?
            o How do we address partial redevelopment?
            o What is the minimum threshold that will require treatment?
   • Comment: FSA did a survey asking MS4s what level of treatment they require locally for
       redevelopment. The survey will be posted to the stormwater rule web site.
   • Comment (John B.): Suggest we use % disturbance of the existing site to determine the
       triggers. We need to distinguish between redevelopment and retrofit projects. A: The
       rule is already drafted that way.
   • Question (Doug): What happens if a WBID has a TMDL with nutrient criteria but the pre
       N and P values were lower than that? Do we just meet the TMDL then? Would focusing
       on the post ≤ pre idea be overkill?
   • Comment (Eric): We want to promote redevelopment, but we just need to establish the
       minimum level of treatment from these areas. Maybe we could assign a minimum of
       25%, then add additional requirements for specific basins?
   • Comment: Maybe we could provide incentives for things like installing the infrastructure
       first for redevelopment projects?
   • Question: Transportation improvements (like putting a new lane on I-4) should be
       classified as redevelopment? A: Probably.
   Issue Paper: Size Threshold (Eric Livingston)
   • We need to determine:
            o Should there be a size threshold for for projects that are required to meet the
                 post ≤ pre requirement?
            o What should the size threshold be?
   New Stormwater Rule – Strawman Handbook (Michael Batemen)
   • The draft of the Stormwater Quality Applicant’s Handbook looks like the new ERP that
       was recently adopted in the panhandle (used that as a platform). This draft will be
       posted on the ftp tomorrow. Chapter 63-347 F.A.C. will be the rule that points to this
       handbook.
   • Part 1: General Criteria. Section 1 includes applicability, definition of stormwater quality
       treatment system (SQT), and compensating treatment. The treatment train efficiency
       equation might change because of diminished return.
   • Part 2: Stormwater Quality. Section 2 includes size thresholds (TBD - to be determined),
       how standards are applied, ‘safe harbor’ language, treatment efficiencies, calculations
       for undeveloped load and post development load, urban redevelopment and altered
       hydrology (TBD).
            o Comment (Eric) – The ‘safe harbor’ language is not intended to be applicable to
                 TMDLs, only stormwater. Not sure how we will address it if we want to have
                 more stringent standards (for TMDLs, etc.)
            o Clarification: When we use the term ‘pre development’ we mean pre disturbance.
                 We should use the term undeveloped to be clearer.
   • Section 3: Looks a lot like the CGP requirements. We hope that the ERP application
       can serve as the CGP NOI in the future if WMDs are recognized as a State agency.
   • Section 4: Includes information on retention systems (treatment volume varies
       depending on the required site treatment efficiency – big difference from previous


SSTR TAC 3-5-08                            10
                                          DRAFT
      requirement), swales, determining treatment volumes, safety factors, and soil
      amendments.
   • Section 5: Includes information on biofiltration and determining treatment volume (needs
      a lot of work).
          o Comment: For any BMP that uses retention, you use Appendix D.
          o Comment (John B.): We are considering underdrains here? Do we need to look
               at soil amendments for these? A: Yes, if it is collected in a pipe and discharged.
               We might need to look at amendments for these.
   • Section 6: Includes information on exfiltration inspection and maintenance, and
      determining treatment volume.
   • Section 7: Includes information on wet detention (more information will be added from
      the work group).
   • Section 8: Includes information on wetland treatment systems (more information will be
      added from the work group).
   • Section 9: Includes information on vegetated natural buffers.
          o Comment (John B.): Where does it talk about littoral zones? A: Currently is not
               in here, but may be added based on the work group information.
   • Section 10: Includes information about stormwater reuse.
          o Comment: What about including withdrawals from a holding device? A: Don’t
               see why not.
   • Section 11: Includes information about LID (more information will be added from the
      work group).
   • Section 12: Includes information about stormwater retrofits (if it is a ‘good citizen project’
      they will be exempt from the rule.
          o Comment: It does not currently include aesthetics, as it is only concerned with
               water quality.
          o Question (Josh): What about minimum pond size criteria? A: That is currently
               part of a sub group.
          o Comment (John B.): It looks like there is some double counting going on in the
               stormwater credit categories (in these soils, you have to have a low impervious
               area for the boxes to work).
   • Sections 13 through 18: These address methodologies for retention systems, detention
      systems, reuse systems, vegetated natural buffers, green roof/ cistern system, and karst
      areas. All this will change as the criteria change (based on the work groups, the TAC
      recommendations, etc.)
   • Comment: We need to discuss the economics of review/ implementation. A: As part of
      any rule making activity, an economic impact statement is required. That will be
      developed next year.
   Next Steps
   • We will plan on holding meeting on the following dates: April 16, May 28, July 9, August
      20, and October 1 from 10 am – 3 pm. We will meet either in Tallahassee, Tampa or
      Orlando.
   • All materials from this meeting will be posted on the website
      (dep.state.fl.us/water/wetlands/erp/rules/sw_swt_rule_dvlpmt.htm). Devo’s information
      about karst is on his website. DEP will post the EPA Q&A of the Harper Method, as well
      as the 3 page Technical Evaluation on the website.
   • All information that a TAC member wants to communicate with the group should be sent
      to Kathy Harrigan at Kathleen.Harrigan@dep.state.fl.us




SSTR TAC 3-5-08                            11
                                       DRAFT
   •   Travel vouchers should be completed and sent to Eric. He will check them over and
       send them back. The TAC member should then print and sign, and send the original
       (with original receipts) to Eric.




SSTR TAC 3-5-08                          12

								
To top