Wetland Functions and Values Fundamentals for Conservation Commissioners Training Program - Unit 5 Fundamentals for Conservation Commissioners Training Program - Unit 5 Massachusetts Association of Conservation Commissions Creation of this Unit was funded in part with a grant from the Massachusetts Environmental Trust. Developed by Scott Jackson of the University of Massachusetts

Wetland Values Flood control Storm damage protection Pollution control Protection of water supply Protection of groundwater Flood control Storm damage protection Pollution control Protection of water supply Protection of groundwater Fisheries and shellfish Wildlife habitat Climate regulation Aesthetics and recreation Education and research Harvest of natural products

Interests Protected by the Act Flood control Storm damage prevention Pollution prevention Public and private water supply Groundwater supply Land containing shellfish Fisheries Wildlife habitat Flood control Storm damage prevention Pollution prevention Public and private water supply Groundwater supply Land containing shellfish Fisheries Wildlife habitat

Salt Marsh

Bog

Forested Swamp

Floodplain Forest

Shrub Swamp

Marsh

Wet Meadow

Wetland Value Wetland Function Capacity: Wetland Characteristics Capacity: Wetland Characteristics Opportunity: Watershed Context Opportunity: Watershed Context

Flood Control: Function Flood storage (reduces flood peaks) Velocity reduction (reduces flow) Desynchronization (staggers flood peaks) Flood storage (reduces flood peaks) Velocity reduction (reduces flow) Desynchronization (staggers flood peaks)

Flood Control: Characteristics Capacity for ponding or flooding Flood ratio Size Associated with watercourse Constricted outlet Sheet vs. channelized flow Dense vegetation (forest or shrub) Roughness Capacity for ponding or flooding Flood ratio Size Associated with watercourse Constricted outlet Sheet vs. channelized flow Dense vegetation (forest or shrub) Roughness

Flood Control: Watershed Context Located just upstream of human settlements or other sensitive areas Large proportion of impervious surfaces Large proportion of steep slopes Channelized waterways into wetland Lakes & wetlands <10% of watershed Located just upstream of human settlements or other sensitive areas Large proportion of impervious surfaces Large proportion of steep slopes Channelized waterways into wetland Lakes & wetlands <10% of watershed

Storm Damage Control: Function Anchor shoreline Dampen waves Reduce current velocity Intercept water Anchor shoreline Dampen waves Reduce current velocity Intercept water

Storm Damage Control: Characteristics Associated with watercourse or water body Dense Vegetation Wetland width >10' Gradual shoreline (erosion) Gradient in wetland (waves) Associated with watercourse or water body Dense Vegetation Wetland width >10' Gradual shoreline (erosion) Gradient in wetland (waves)

Storm Damage Control: Watershed Context Coastal areas Open water fetch >2000 ft. High water velocities Downstream of channelized waterway Downstream of water release dam Potential for boat wakes Coastal areas Open water fetch >2000 ft. High water velocities Downstream of channelized waterway Downstream of water release dam Potential for boat wakes

Physical Chemical Biological Pollution Control: Function Wetlands remove pollutants using several processes

Important Pollutants Toxic materials Sediment Nutrients Toxic materials Sediment Nutrients

Pollution Control: Characteristics Capacity for ponding or flooding Flood ratio Water retention Constricted outlet Gentle wetland gradient Sheet vs. channelized flow Size Capacity for ponding or flooding Flood ratio Water retention Constricted outlet Gentle wetland gradient Sheet vs. channelized flow Size Aerobic/anaerobic soil interface Duration saturation/shallow inundation Dense vegetation (floating, emergent) Organic soils Shellfish beds

Pollution Control: Watershed Context Upstream of water supply or other sensitive areas Proximity to pollution sources Large proportion of impervious surfaces Lakes & wetlands <10% of watershed Upstream of water supply or other sensitive areas Proximity to pollution sources Large proportion of impervious surfaces Lakes & wetlands <10% of watershed

Protection of Water Supply: Function Water Quality Removing pollutants Water Quantity Detaining and releasing runoff and floodwater Groundwater discharge Water Quality Removing pollutants Water Quantity Detaining and releasing runoff and floodwater Groundwater discharge

Groundwater Discharge: Indicators Presence of springs Surface outflow exceeds surface inflow Persistent flow Consistent water temperature Outlet only Topographic position Large size relative to catchment area Presence of springs Surface outflow exceeds surface inflow Persistent flow Consistent water temperature Outlet only Topographic position Large size relative to catchment area

Boelter and Verry 1977 Horizontal Water Flow Rate as a Function of Depth Below the Surface in Organic Wetlands

Protection of Water Supply: Watershed Context Located in deposits of stratified drift Upstream of water supply or other sensitive areas Proximity to pollution sources Large proportion of impervious surfaces Lakes & wetlands <10% of watershed Located in deposits of stratified drift Upstream of water supply or other sensitive areas Proximity to pollution sources Large proportion of impervious surfaces Lakes & wetlands <10% of watershed

Protection of Groundwater: Function Removing pollutants Groundwater recharge Removing pollutants Groundwater recharge

Groundwater Recharge: Mechanisms Perched wetlands Floodplains Bank storage Seasonal recharge Perched wetlands Floodplains Bank storage Seasonal recharge

Confining Layer (hard pan) Aquifer Water Table Recharge Perched Wetland

Bank Storage Recharge Flood Level Normal Water Level Impervious Wetland Soil Pervious Soil

Groundwater Recharge: Characteristics (where recharge function is present) Association with watercourse Perched wetland Somewhat permeable soils Variable water levels High edge-to-volume ratio Association with watercourse Perched wetland Somewhat permeable soils Variable water levels High edge-to-volume ratio

Protection of Groundwater: Watershed Context Public or private wells down gradient Significant wetlands or watercourse down gradient Proximity to pollution sources Large proportion of impervious surfaces Associated with a significant aquifer Located in deposits of stratified drift Public or private wells down gradient Significant wetlands or watercourse down gradient Proximity to pollution sources Large proportion of impervious surfaces Associated with a significant aquifer Located in deposits of stratified drift

Shellfish Habitat: Function Provide appropriate substrates Food chain support Maintenance of water supply Maintenance of water quality Provide appropriate substrates Food chain support Maintenance of water supply Maintenance of water quality

POM NO 2 Food Chain Support Plants Nutrient Uptake Organic Debris Invertebrates Debris Processing

Shellfish Habitat: Characteristics (coastal areas and directly upstream) Salt marsh and/or tidal flats present Unrestricted tidal hydrology Water quality Productivity/POM export Connection with waterway supporting shellfish Capacity to remove pollutants Salt marsh and/or tidal flats present Unrestricted tidal hydrology Water quality Productivity/POM export Connection with waterway supporting shellfish Capacity to remove pollutants

Fish Habitat: Function Spawning areas Nursery habitat Cover Food chain support Maintenance of water supply Maintenance of water quality Spawning areas Nursery habitat Cover Food chain support Maintenance of water supply Maintenance of water quality

Fish Habitat: Characteristics Connection with permanent water Presence of springs Water chemistry Temperature No channelization Pools at low water Natural fluctuation in water level Cover and shade Connection with permanent water Presence of springs Water chemistry Temperature No channelization Pools at low water Natural fluctuation in water level Cover and shade

Wildlife Habitat: Function Breeding areas Foraging areas Shelter Over-wintering areas Migratory routes Food chain support Maintenance of water supply Maintenance of water quality Breeding areas Foraging areas Shelter Over-wintering areas Migratory routes Food chain support Maintenance of water supply Maintenance of water quality

Wildlife Habitat: Characteristics Diversity of wetland classes Interspersion of vegetation and open water Diversity of vegetation (vertical and horizontal) Surrounding habitat Water chemistry Scarcity Special habitat features Diversity of wetland classes Interspersion of vegetation and open water Diversity of vegetation (vertical and horizontal) Surrounding habitat Water chemistry Scarcity Special habitat features

Wildlife Habitat: Examples of Special Habitat Features Vernal pools Saltwater pans Mud flats Undercut banks Vertical sandy banks Underwater banks of fine silt & clay Sphagnum hummocks and pools Large cavity trees Vernal pools Saltwater pans Mud flats Undercut banks Vertical sandy banks Underwater banks of fine silt & clay Sphagnum hummocks and pools Large cavity trees

Special Habitat Features

New Hampshire Method New Hampshire Method

New Hampshire Method: Ground Water Use Potential New Hampshire Method: Ground Water Use Potential

Buttonbush River Open Water Marsh Gas Pipeline (Limited Project) Floodplain Forest

Detention Basin Mall Parking Lot Forested Swamp Permanent Open Water Perennial Stream Access Road Replication Area