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					                     The LaPlatte River

   Phase I Geomorphic
       Assessment
                            Cully’s House


        Andrea Pearce
        Erin Copeland

           May 6, 2004


The LaPlatte River
Phase I Geomorphic
                        Objectives
   Background to the Story…Physical Setting of the LaPlatte River

   Why we wrote this story...Purpose and Scope of a Phase I
    Geomorphic Assessment

   How we wrote this story…Methodology

   What we learned through the completion of the story…Results

   The End of the Story…Conclusions

   What our editor said…Recommendations



The LaPlatte River
Phase I Geomorphic
 Introduction to the LaPlatte River
            Watershed

                        Towns: Charlotte and
                         Hinesburg,
                         Chittenden County,
                         VT

                        Watershed Area: 31
                         mi 2


The LaPlatte River
Phase I Geomorphic
 Introduction to the LaPlatte River
            Watershed
   Physical Setting
        Glacial History of the Champlain Valley:
             Formerly occupied by a large glacial lake and sea.
             Deposition of different sized sediment due to the migration
              of the glacial lake and sea.
        Soils:
             Winooski very fine sandy loam / Limerick silt loam
             Alluvium with high erodibility
        Land Use
             >50% in agriculture
             >50% of the riparian buffer is between 0-25 feet wide
             8 road crossings and 1 golf course

The LaPlatte River
Phase I Geomorphic
                     Purpose and Scope
   Discover basic physical parameters
   Evaluate reach condition, impact score and
    sensitivity
   Provides preliminary assessment
        1st cut to identify areas for more in depth geomorphic
         assessments
   Phase I Geomorphic Assessment Products:
        Reference Stream Typing, Stream Impact Rating,
         Provisional Stream Geomorphic Score, Like Reach
         Evaluation
The LaPlatte River
Phase I Geomorphic
                     Methodology
                              Followed VTANRP1GA
                               protocol
                              Used GIS, appropriate
                               existing data layers, and
                               created map layers
                              Windshield Survey
                                  More detail to follow
                              Database computation
                               using the
                               VTANRP1GADB
                              Synthesis
                                  Reach process evaluation
                                   and recommendations


The LaPlatte River
Phase I Geomorphic
                 Windshield Survey
   Used the multiple
    road crossings
   We were able to
    chat with one
    landowner
   Visualized the
    reach groupings
   Recommendations
    stemmed from field
    observations

The LaPlatte River
Phase I Geomorphic
Results:
Reach
Condition
by
Sub-
Watershed



The LaPlatte River
Phase I Geomorphic
                     Results




The LaPlatte River
Phase I Geomorphic
                                                   Results
                                           Portion of Like Reach Assessment

                                    100%
         River Adjustment Process




                                    80%


                                    60%                                       Planform
                                                                              Widening
                                                                              Aggrading
                                    40%                                       Degrading

                                    20%


                                     0%
                                           M1 M2 M3 M4 M5 M6 M7 M8 M9
                                                     Reach Number

The LaPlatte River
Phase I Geomorphic
                     Conclusions
                              River was straightened
                               prior to 1978
                                  From M5 – M8 ~88% of the
                                   mainstem has been
                                   straightened
                                  Historic orthophotos show
                                   many oxbows and
                                   wetlands

                              Land use
                                  Agriculture dominates
                                  However little urban
                                   development on the
                                   floodplain


The LaPlatte River
Phase I Geomorphic
                     Conclusions
   Land use (continued)
        (sub) Urban areas: Hinesburg and
         surrounding areas
        One golf course on M8 & M9, the uppermost
         reaches

   Stream typing is perplexing
        Either the classification system is confusing or
        It is an indication of impairment

The LaPlatte River
Phase I Geomorphic
                           Conclusions
   Ecological Concerns
        Substrate is uniform
             Little in-stream habitat
              differentiation for
              macroinvertebrates & fish
        Little riparian buffer
             Corridor travel is lessened
             No shade
             Little CWD input
        Possible phosphorous &
         sediment contributor to
         Lake Champlain


The LaPlatte River
Phase I Geomorphic
            Recommendations:
 Synthesis of visual, cultural and scientific
                information

                        Recommendation Priorities

                          Low: M1, M2, M4 and M7
                          Medium: M3, M9
                          High: M5, M6, M8




The LaPlatte River
Phase I Geomorphic
    Recommendations: Low Priority
   M1, M2, M4 & M7
        Similarities
             Vegetation
             M1,M2 & M4 have
              natural meanders
             M7 does not, however
              has riparian buffer


        Recommendations
             Plant woody
              vegetation: shrubs and
              trees
The LaPlatte River
Phase I Geomorphic
        Recommendations: Medium
               Priority
                        M3, M9
                            Similarities
                                 Natural channel shape
                                 Mild erosion
                                 Development Pressure


                            Recommendations
                                 Buffer plantings
                                 Zoning laws




The LaPlatte River
Phase I Geomorphic
    Recommendations: High Priority
   M5, M6 & M8
        Similarities
             Straightened channel
             Little riparian buffer
             Steep banks (5-15ft)


        Recommendations
             Phase II & III to create
              natural meanders and
              stabilize banks
             Buffer plantings
             Education opportunities
              for students

The LaPlatte River
Phase I Geomorphic
                     In conclusion…
   Notable river impairment: Straightening, eroded
    banks, possible sedimentation, little riparian
    buffer
   River adjustment processes: Degrading, some
    widening
   Zoning / planning in Charlotte & Hinesburg
    (M3, M9)
   Monitoring plan for restoration projects
   Involve community in river education and
    restoration

The LaPlatte River
Phase I Geomorphic
                     Soil Samples?

                       Any questions…




The LaPlatte River
Phase I Geomorphic

				
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