Wetland Buffers The White Paper Robert Jontos PWS

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

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

Status of Buffers in Connecticut Summary of 2003 Presentation: – Legal Authority - Municipal Inland Wetland 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 3 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 4 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Vegetative Buffer - 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. Common Names: “Buffer Area” “Vegetative Buffer Strip” – VBS Interchangeable terms 5 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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. 6 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Regulated Area or Setback Regulated area or setback watercourse & wetland Regulated Area or Setback is a distance from a wetland or watercourse which is defined by local Land Use Agencies February 25, 2003 CAWS 7 th Annual Meeting - Buffers 7

Riparian Area s d an l up s n ai pl od o l f p od nd tla e w nd l n ai l up d an flo tla we watercourse Riparian Area is defined as the lands immediately adjacent to a watercourse up to the limits of the floodplain 8 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Vegetated Buffer vegetated buffer watercourse & wetland Existing vegetation and turf Vegetated Buffer shown – native planted strip between wetland/watercourse and upland existing vegetation February 25, 2003 CAWS 7 th Annual Meeting - Buffers 9

Summary of 169 Municipal Regulations “Regulated Areas” General Setback Wetland Setback Watercourse Setback Buffer 87 40* 13 Range (FT) 20 - 650 Range (FT) 15 - 100 Range (FT) 15 – 100 Range (FT) 50 - 200 * 16 COMMUNITIES WITH VARIABLE DISTANCES 19 COMMUNITIES USE RESOURCE SPECIFIC SETBACKS 6 COMMUNITIES INCREASE SETBACK WITH SLOPES > 10 -15% 2 COMMUNITIES USE FLOOD BOUNDARIES 10 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Summary of 169 Municipal Regulations “Regulated Areas” Number of Towns with setback distance 20’ 25’ 50’ 75’ 80’ 100’ 150’ 200’ 250’ >250’ 1 0 1 4 1 8 1 2 0 1 11 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 12 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

2003 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 13 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

2003 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 14 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

2004 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 15 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Vegetative Buffer White Paper Motivation: - Science based methodology for design, regulation and effective management of vegetative buffers - Version 1. 0 - Working document - Initial focus: Protecting and improving water quality 16 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 17 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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

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

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

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 21 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 22 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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. 8 L/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 23 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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

Welsch (1991) “Three Zone Method” Zone Width Purpose 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 (10 200 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) February 25, 2003 CAWS 7 th Annual Meeting - Buffers 25

Sweeney (1992) Modified Three Zone Method Zone Width Purpose 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 Slow runoff, filter sediment Upland edge of zone #2 promote infiltration, to 6. 1 m (20 ft) landward nutrient uptake, and sheet flow Zone #1 - Trees (after Sweeney, 1992) February 25, 2003 CAWS 7 th Annual Meeting - Buffers 26

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 27 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Selecting Buffer Widths: Additional Methods • Connecticut Guidelines for Sediment and Erosion Control 2002 (50 ft to >1600 ft, 10% max. slope ) • Finley (1987) 15 m (49 ft) starting width, increase 6 m (19. 7 ft) for each 5% increase in slope to a maximum slope of 25% and 150 feet width 28 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Effective Buffer Area Drainage Area Riparian Buffer Zone Effective Buffer Area Wetland Watercourse Gross Area of Buffer Modified after Dossky et al. 2002 February 25, 2003 CAWS 7 th Annual Meeting - Buffers 29

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 30 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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

Buffer Size: Recommend Width for Water Quality • Observations from the literature reviewed: • Width of VBS range between 2 - 500 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 32 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Buffer Size: Recommend Width for Water Quality 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 33 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Plant Type vs. Removal Efficiency Function Grass Shrubs Trees Sediment Trapping High Medium Low Filtration of Sediment Borne Nutrients, Microbes & Pesticides High Low Soluble Nutrients & Pesticides Removal Medium Low Medium Flood Conveyance High Low Medium High Reduce Streambank Erosion Mod. after Fisher & Fischenich, 2000 February 25, 2003 CAWS 7 th Annual Meeting - Buffers 34

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 35 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Plant Species, Numbers & Sizing Tree Diversity Number of Trees Planted Max. % of any one species 10 -19 50% 20 - 39 33% 40 or more 25% • Fisher and Fischenich, 2000) 36 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Plant Species, Numbers & Sizing Tree Planting Densities: • 400/acre, 10” to 48” tall • 200/acre, 15 ft tall • 3 - 5 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 37 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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. 38 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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, nonpoint nutrient and pollutant removal, promotes infiltration 39 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 40 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 41 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 longterm management plan. 42 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 – 5 m (16 ft) to 15 m (49 ft) effective in reducing sediment loads and protecting water quality 43 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Observations & Recommendations • In Urban/agricultural areas with slopes of <10% with limited area, 5 m 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 10 m (33 ft) can be effective. 44 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 10 m + (50 ft or greater) should be considered with BMPs 45 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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 46 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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. 47 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

Information • CAWS web address: www. ctwetlands. org • My email address: rjontos@landtechconsult. com • 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 48 February 25, 2003 CAWS 7 th Annual Meeting - Buffers

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