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The White Paper Connecticut Association of Wetland Scientists 7 th Annual Meeting February 25, 2004 Robert Jontos, PWS, CPESC Land-Tech Consultants, Inc.

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Presentation on theme: "The White Paper Connecticut Association of Wetland Scientists 7 th Annual Meeting February 25, 2004 Robert Jontos, PWS, CPESC Land-Tech Consultants, Inc."— Presentation transcript:

1 The White Paper Connecticut Association of Wetland Scientists 7 th Annual Meeting February 25, 2004 Robert Jontos, PWS, CPESC Land-Tech Consultants, Inc. Environmental Scientists and Engineers Wetland Buffers

2 February 25, 2003CAWS 7th Annual Meeting - Buffers2 Status of Buffers in Connecticut Topics to be covered: Summary of 2003 Presentation Introduction Objectives Findings Recommendations

3 February 25, 2003CAWS 7th Annual Meeting - Buffers3 Status of Buffers in Connecticut Summary of 2003 Presentation: –Legal Authority - Municipal Inland Wetland and Watercourses Agencies can regulate activities outside of their jurisdictional areas provided that: Buffers are provided for in their regulations Proposed upland site activities will or may affect jurisdictional areas

4 February 25, 2003CAWS 7th Annual Meeting - Buffers4 Terminology Defined “Setback Area” and “Non-disturbance Area” -Often used interchangeably with the term buffer, but not interchangeable for the purposes of the white paper -Physical dimension -Vegetation may not be managed “Upland Review Area” -Not a buffer, but a dimensioned distance from a wetland or watercourse “Riparian Area” -The land immediately adjacent to a watercourse -Lake, pond, or stream

5 February 25, 2003CAWS 7th Annual Meeting - Buffers5 Vegetative Buffer - Definition Common Names: “Buffer Area” “Vegetative Buffer Strip” – VBS Interchangeable terms Definition: Typically defined as a vegetative upland area (determined by soils, topography and vegetation) directly adjacent to a wetland or watercourse with ecological, hydrologic and physical connections to the wetland or watercourse.

6 February 25, 2003CAWS 7th Annual Meeting - Buffers6 Buffer vs Vegetative Buffer “Buffer” Setback, non-disturbance area, or upland review area; a physical dimension only “Vegetative Buffer” Functional entity used to treat stormwater runoff, and enhance/protect/preserve water quality.

7 Regulated Area or Setback Regulated Area or Setback is a distance from a wetland or watercourse which is defined by local Land Use Agencies watercourse & wetland Regulated area or setback

8 watercourse floodplain wetland floodplain uplands Riparian Area Riparian Area is defined as the lands immediately adjacent to a watercourse up to the limits of the floodplain

9 Vegetated Buffer Vegetated Buffer shown – native planted strip between wetland/watercourse and upland existing vegetation Existing vegetation and turf watercourse & wetland vegetated buffer

10 February 25, 2003CAWS 7th Annual Meeting - Buffers10 General Setback Wetland Setback Watercourse Setback Buffer 8740* 13 Range (FT) Range (FT) Range (FT) 15 – 100 Range (FT) * 16 COMMUNITIES WITH VARIABLE DISTANCES 19 COMMUNITIES USE RESOURCE SPECIFIC SETBACKS 6 COMMUNITIES INCREASE SETBACK WITH SLOPES > 10-15% 2 COMMUNITIES USE FLOOD BOUNDARIES Summary of 169 Municipal Regulations “Regulated Areas”

11 February 25, 2003CAWS 7th Annual Meeting - Buffers11 20’25’50’75’80’100’150’200’250’>250’ Number of Towns with setback distance Summary of 169 Municipal Regulations “Regulated Areas”

12 February 25, 2003CAWS 7th Annual Meeting - Buffers12 Summary of 169 Municipal Regulations “Regulated Areas” Not all communities have setbacks cited in their regulations Setback distances cover a broad range of distances, variables (slope angle, land use) Some communities use resource specific setbacks (river, watershed, floodplain) None cite a methodology for determining “buffer” width

13 February 25, 2003CAWS 7th Annual Meeting - Buffers Buffer Conclusions 1) Buffer regulations don’t consider individual buffer functions nor the characteristics or condition of the buffer. 2) Buffer size is either “fixed” or “variable” Fixed width – easily enforced, existing and proposed conditions not considered Variable width - Considers site specific conditions, trained staff, variability

14 February 25, 2003CAWS 7th Annual Meeting - Buffers Buffer Conclusions Combined Approach: a) Education – designers, reviewers and “the Public” b) Accepted and defensible protocol for design & application c) Combine with LID & BMPs d) Maintenance/Management e) Enforcement

15 February 25, 2003CAWS 7th Annual Meeting - Buffers Vegetative Buffer White Paper -Drafted by CAWS members for use by designers and regulatory agencies & commissions - Academically and legally critiqued - Purpose: education, design parameters, review criteria, management methods

16 February 25, 2003CAWS 7th Annual Meeting - Buffers16 Vegetative Buffer White Paper Motivation: - Science based methodology for design, regulation and effective management of vegetative buffers - Version Working document - Initial focus: Protecting and improving water quality

17 February 25, 2003CAWS 7th Annual Meeting - Buffers17 Vegetative Buffer Functions 1. Sediment removal (filtration) 2.Nutrient removal (plant uptake & soil adsorption) 3.Stormwater runoff (filtration & infiltration) 4.Water temperature moderation 5.Habitat and wildlife diversity

18 February 25, 2003CAWS 7th Annual Meeting - Buffers18 Buffer Sizing and Design General Considerations -“one size does not fit all” 1.Objectives must be defined 2.Watershed position 3.Existing plant composition and density 4.Soils and Slope conditions (above & within buffer area)

19 February 25, 2003CAWS 7th Annual Meeting - Buffers19 Buffer Sizing and Design Objectives: 1.Runoff filtration & infiltration 2.Streambank stabilization 3.Downstream flood attenuation 4.Wildlife habitat and corridors

20 February 25, 2003CAWS 7th Annual Meeting - Buffers20 Buffer Sizing and Design Watershed position 1.Position does impact effectiveness 2.Buffering low order streams (1st-3rd), greater impact on water quality than wider buffers on large order streams – sediment source control

21 February 25, 2003CAWS 7th Annual Meeting - Buffers21 Buffer Sizing and Design Existing plant composition and density Inventory existing species & density Use “undisturbed” riparian community as guide for enhancement/management Ground cover critical element Microtopgraphy within buffer area may permit channeling of surface flow

22 February 25, 2003CAWS 7th Annual Meeting - Buffers22 Buffer Sizing and Design Soils and Slope Placement of well developed vegetative buffer strip (VBS) between erosive soils or soils exposed for extend periods reduces the velocity of runoff, thus reducing scour potential & sediment movement, and promotes sheet flow/infiltration

23 February 25, 2003CAWS 7th Annual Meeting - Buffers23 Buffer Size: Recommend Width for Water Quality Approaches: 1.Regression analysis (Dillaha, et al., 1986) quantify buffer performance based on sediment, nitrogen and phosphorus removal - Based on limited database, low flow rates (1.8L/s-m), narrow buffers <11.2 meters - Site specific, slope not considered - Requires subshed runoff to be calculated using standard engineering analysis - Trial and error, checking tool

24 February 25, 2003CAWS 7th Annual Meeting - Buffers24 2.Welsch (1991) “Three Zone Method” 3.Sweeney (1992) modified “Three Zone” fixed width Three Zone method for riparian forest restoration 4.Westchester Environmental Management Council Method considers slope Buffer Size: Recommend Width for Water Quality

25 February 25, 2003CAWS 7th Annual Meeting - Buffers25 ZoneWidthPurpose Zone #1- Trees T.O.B to 5-8 m (15-25 ft) landward Bank stabilization, moderate water temperature, promote algal growth, woody debris input, nutrient & detritus processing Zone #2 – Trees & Shrubs Landward edge of zone #1 to 3 to >100 m ( ft) Long-term sequestering of nutrients, sediments, and other pollutants, runoff infiltration Zone #3- Grass or Herbaceous Upland edge of #2 to 3 meters if used with zones 1 & 2, or 10.6 m (35 ft) alone. Slow runoff, filter sediment promote infiltration, nutrient uptake, and sheet flow (after Welsch, 1991) Welsch (1991) “Three Zone Method”

26 February 25, 2003CAWS 7th Annual Meeting - Buffers26 ZoneWidthPurpose Zone #1- Trees T.O.B to 4.6 m (15 ft) landward Bank stabilization, moderate water temperature, promote algal growth, woody debris input,nutrient & detritus processing Zone #2 – Trees & Shrubs Landward edge of zone #1 to 18 m (60 ft) Long-term sequestering of nutrients, sediments, and other pollutants, runoff infiltration Zone #3- Grass or Herbaceous Upland edge of zone #2 to 6.1 m (20 ft) landward Slow runoff, filter sediment promote infiltration, nutrient uptake, and sheet flow Sweeney (1992) Modified Three Zone Method (after Sweeney, 1992)

27 February 25, 2003CAWS 7th Annual Meeting - Buffers27 Westchester County Method (1981) Minimum starting buffer width of 7.6 m (25 ft) Increase buffer width by 0.9 meters (3.0 ft) for each percent (%) increase in slope Reduce buffer width by 0.1 meters (1.0 ft) for each 0.9 meter (3 ft) of adjacent brush or woodland growth in good hydrologic condition Slopes >15% and/or slope runs > 200 ft and/or if filter is in dense shade or subject to heavy traffic, then temporary E&S controls and level spreader required

28 February 25, 2003CAWS 7th Annual Meeting - Buffers28 Selecting Buffer Widths: Additional Methods Connecticut Guidelines for Sediment and Erosion Control 2002 (50 ft to >1600 ft, 10% max. slope ) Finley (1987) 15m (49 ft) starting width, increase 6m (19.7 ft) for each 5% increase in slope to a maximum slope of 25% and 150 feet width

29 February 25, 2003CAWS 7th Annual Meeting - Buffers29 Effective Buffer Area Drainage Area Riparian Buffer Zone Effective Buffer Area Wetland Watercourse Modified after Dossky et al Gross Area of Buffer

30 February 25, 2003CAWS 7th Annual Meeting - Buffers30 Physical Environment Soil Type – Drainage class/hydrologic group, erodibility Index Topography – Greater the slope, faster the runoff, increase in soil erosion and sediment transport potential “Area Ratio” - size of the drainage area contributing flow to the buffer, smaller the ratio, better the treatment

31 February 25, 2003CAWS 7th Annual Meeting - Buffers31 Area Ratio watercourse V.B.S Drainage area

32 February 25, 2003CAWS 7th Annual Meeting - Buffers32 Buffer Size: Recommend Width for Water Quality Observations from the literature reviewed: Width of VBS range between meters/ 6.5 – 1,640 feet Majority fall within 4.6 – 15 meters/15 – 49 feet. Slope of buffer >10%, increase in width Area ratio range 15:1 to 5:1 or less Plant species composition affects efficiency

33 February 25, 2003CAWS 7th Annual Meeting - Buffers33 Plant Composition: 1.Grass – effective in removing coarse sediment and absorbing nutrients 2.Shrubs – maintain soil infiltration capacity 3.Combined grass and shrub filter more effective than grass alone 4.Ideal VBS is transition - grass, shrubs and trees Buffer Size: Recommend Width for Water Quality

34 February 25, 2003CAWS 7th Annual Meeting - Buffers34 Plant Type vs. Removal Efficiency FunctionGrassShrubsTrees Sediment Trapping HighMediumLow Filtration of Sediment Borne Nutrients, Microbes & Pesticides HighLow Soluble Nutrients & Pesticides Removal MediumLowMedium Flood Conveyance HighLow Reduce Streambank Erosion MediumHigh Mod. after Fisher & Fischenich, 2000

35 February 25, 2003CAWS 7th Annual Meeting - Buffers35 Plant Species, Numbers & Sizing Diversity of plant species within the buffer insure better success in response to variable environmental conditions (temp., herbivory water levels) A mixture of native herbaceous, shrub and tree species appropriate to the environment Habitat Diversity – variable amounts and types of plants, over microtopography

36 February 25, 2003CAWS 7th Annual Meeting - Buffers36 Plant Species, Numbers & Sizing Tree Diversity Number of Trees PlantedMax. % of any one species % % 40 or more25% Fisher and Fischenich, 2000)

37 February 25, 2003CAWS 7th Annual Meeting - Buffers37 Plant Species, Numbers & Sizing Tree Planting Densities: 400/acre, 10” to 48” tall 200/acre, 15 ft tall ft tall saplings spaced 15 feet on center may reduce negative impacts of browse, better survival Shrub planting – 2-3 feet tall, 5-8 feet on center

38 February 25, 2003CAWS 7th Annual Meeting - Buffers38 Plant Survival Management Measures: Use of plastic tree shelters with mulch and herbicide, best seedling survival Grasses harvested to encourage dense growth, remove nutrients Control invasives – mechanical, hand, mulch, herbicide or prescribed burning Remove sediment, fill rills and re-create microtopography and re-seed/replant.

39 February 25, 2003CAWS 7th Annual Meeting - Buffers39 Observations & Recommendations 1.Vegetative buffer strips (VBS) are an effective BMP in urban and agricultural settings. One-size does not fit all, bigger may not be better due to channelized flow 2.Vegetation provides E&S control, non- point nutrient and pollutant removal, promotes infiltration

40 February 25, 2003CAWS 7th Annual Meeting - Buffers40 Observations & Recommendations 3.Buffer Effectiveness dependent upon: a) Species and density of vegetation within the buffer b) Soil type above and within the buffer c) Slope of the buffer and contributing watershed area – microtopgraphy d) Length of the buffer (width of flow path) and Area ratio e) Proposed land use above the buffer

41 February 25, 2003CAWS 7th Annual Meeting - Buffers41 Observations & Recommendations 4.VBS can be used as stand alone BMP, but are more effective when used in combination with other BMPs/LIDs 5.Long continuous buffer strip rather than segmented, can be variable in width depending on site conditions and design goals

42 February 25, 2003CAWS 7th Annual Meeting - Buffers42 Observations & Recommendations 6.Combination of grass, shrub & trees in sequence more effective in removing sediment, adsorbing nutrients, other NPS pollutants and maintaining soil infiltration 7.Native species should be used to enhance or create VBS in combination with long- term management plan.

43 February 25, 2003CAWS 7th Annual Meeting - Buffers43 Observations & Recommendations 8.Infiltration is key to reducing sediment and adsorbing pollutants 9.Smaller area ratios (5:1) are more effective in sustaining filtering efficiency of VBS 10.Buffer widths – 5m (16ft) to 15m (49ft) effective in reducing sediment loads and protecting water quality

44 February 25, 2003CAWS 7th Annual Meeting - Buffers44 Observations & Recommendations In Urban/agricultural areas with slopes of <10% with limited area, 5m wide grass VBS are effective in removing significant amounts of NPS pollutants In watersheds under development with slopes 10% or less and typical soil transitions, a minimum buffer of 10m (33 ft) can be effective.

45 February 25, 2003CAWS 7th Annual Meeting - Buffers45 Observations & Recommendations With slope conditions >10% and: –wetlands & watercourses with moderate to high functional values or critical habitats (bogs, fens, wetland complexes) –or where water quality is a critical issues (public water supply watershed or impaired watercourse) A minimum buffer of 10m + (50 ft or greater) should be considered with BMPs

46 February 25, 2003CAWS 7th Annual Meeting - Buffers46 Observations & Recommendations Functional goals of the Vegetative Buffer Strip must be clearly defined and a management plan prepared to establish and maintain those functional goals both during and after development

47 February 25, 2003CAWS 7th Annual Meeting - Buffers47 Conclusion Now its your turn! Version 1.0 will be posted on the CAWS website for three months for review and comment. White Paper committee will review the comments and edit the paper. Final version will be posted in August of 2004.

48 February 25, 2003CAWS 7th Annual Meeting - Buffers48 Information CAWS web address: My address: please send comments and edits to R. Jontos for distribution to the review committee Please track your changes or use colored fonts or highlighting to make your edits or comments stand out

49 The White Paper Connecticut Association of Wetland Scientists 7 th Annual Meeting February 25, 2004 Robert Jontos, PWS, CPESC Land-Tech Consultants, Inc. Environmental Scientists and Engineers Wetland Buffers


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