MBLR Watershed Shoreland Survey

A watershed is the land area drained by a particular river or lake system. Watersheds are defined by the contours of the land and form natural, large-scale ecological units within the landscape. Every drop of rain and every flake of snow that falls upon the land becomes part of some watershed.

Overview

About 20 coastal watersheds comprise the York County, Maine landscape. To help maintain high-quality water resources throughout York County, the Wells National Estuarine Research Reserve (Wells NERR) and its community partners are surveying watershed shorelands and sharing their findings. These results can be incorporated into community-based watershed management plans.

This summary discusses the Merriland River, Branch Brook, Little River (MBLR) watershed shoreland survey. For this survey, trained volunteers walked along specified stream segments and documented potential inputs of non-point-source pollution within the 250-foot shoreland zone. By and large, the MBLR watershed's shorelands are undisturbed, providing the best possible protection against sources of non-point-source pollution. At several locations, however, specific human activities and land uses have the potential to degrade water resource quality significantly over time, unless changes are made in the short term.

The MBLR Watershed

The Little River is formed from the convergence of two freshwater waterways, the Merriland River and Branch Brook, that flow into a tidal marsh-estuarine ecosystem. The MBLR watershed encompasses sections of Sanford, Kennebunk, and Wells. Dominant land cover in the Little River watershed is a softwood/hardwood mix, covering over 83% of the land. As of 1991, only 6% of the watershed land area was developed, but in recent years the watershed has experienced increased development pressure.

The MBLR watershed is important to freshwater, estuarine, and marine fish, as well as diadromous fish that migrate between the sea and inland waters. Wells NERR researchers have identified 45 finfish species in the watershed. Branch Brook is considered exemplary southern Maine habitat for native fish in the salmon family (such as brook trout), and the Merriland River has abundant high quality spawning habitat for rainbow smelt and river herring. The Little River is an important feeding ground for juvenile striped bass, and anecdotal reports describe sea run brown trout and Atlantic salmon taken from its channels.

The Kennebunk, Kennebunkport, Wells (KKW) Water District uses the Branch Brook aquifer as a public water supply for the towns of Kennebunk, Kennebunkport, Wells, and Ogunquit, and for parts of Arundel, Biddeford, and York. The aquifer has been a reliable source of drinking water for more than a century, but with a growing year-round and three-season population comes concern about harmful chemicals, nutrients, and bacteria. To minimize these threats and to protect the integrity of the groundwater aquifer, the water district owns 803.5 acres of land in the watershed, mostly associated with the Branch Brook sub-watershed.

Through extensive water quality sampling in the Little River estuary, Wells NERR has found that fecal coliform contamination in the estuary originates from freshwater runoff within the Branch Brook and Merriland River portions of the watershed. Non-point-source pollution (NPS pollution; see below) from upstream degrades water quality downstream, preventing clam harvesting throughout the estuary and posing a potential health hazard to swimmers.

The Shoreland Survey

Teams of trained volunteers surveyed specific stream segments. They described on standard data sheets all potential NPS inputs observed within the 250-foot shoreland zone along each river bank. Input types were categorized and ranked in terms of potential disturbance to the watershed.

Surface erosion from runoff in upland areas was the most abundant NPS pollutant, followed by road runoff. Trash, debris, and stream bank erosion were also frequently observed. Other structures and activities likely to have a negative impact on water quality included:

• small, clogged, or poorly placed culverts
• lack of vegetated buffer zones between potential NPS pollution sites (such as homes, farms, etc.) and waterways
• erosion and sediment inputs from all-terrain vehicle use
• construction activities
• pipe discharge, and
• livestock, domestic waterfowl, and agriculture.

Next Steps

For the remainder of 2002, the MBLR Watershed Steering Committee will be seeking community input as they incorporate the results of the MBLR Watershed Shoreland survey into a management plan for the MBLR watershed. The goals of the management plan are:

• to outline strategies for reducing non-point source pollution,
• to prevent new non-point sources from becoming established, or to minimize their impacts, and
• to restore the quality of water resources.

Contact Us

For a complete copy of the Merriland, Branch, Little River (MBLR) Watershed Shoreland Survey, or for other information regarding the watershed, the shoreland survey, or the watershed management planning process, please contact:

Tin Smith, Stewardship Coordinator
Wells NERR
342 Laudholm Farm Road
Wells, Maine 04090
(207) 646-1555 x119
tsmith@wellsnerrcec.lib.me.us

Kristen Whiting-Grant
Maine Sea Grant Extension Associate
342 Laudholm Farm Road
Wells, Maine 04090
(207) 646-1555 x115
kristen.whiting-grant@maine.edu

Background on Watersheds and Non-Point-Source Pollution

Waterways are subject not only to inputs from obvious sources of pollution such as discharge pipes, but also to surface water runoff that travels through the watershed accumulating pollutants as it moves. These diffuse, hard-to-measure inputs are referred to collectively as non-point-source (NPS) pollution. All water within the MBLR watershed has the potential to become contaminated by materials that are present due to human alterations of the watershed landscape.

Natural landscapes have a large capacity to protect water resources. Vegetation allows rainwater to soak into the ground, filter through the substrate, and recharge a watershed's groundwater supply. The forest canopy, subcanopy, and shrub layer intercept raindrops, breaking them into smaller droplets that flow along leaves, branches, and trunks before reaching the forest floor. Leaf litter provides further protection for fragile forest soils, allowing water to seep downward, preventing compaction, erosion, and surface water runoff during heavy rains. The deep, well-developed root systems of woody plants also stabilize forest soils and help them retain moisture and pollutants or nutrients that would otherwise seep into ground water.

As a landscape is developed, it typically becomes progressively hardened or "impervious," preventing rainwater from seeping through soils. Rain that falls upon rooftops, pavement, and manicured lawns rapidly runs off, carrying pesticides and herbicides from lawns and gardens, hydrocarbons from leaked car lubricants, and nutrients from fertilizers into the nearest watercourse. Runoff creates high flows; freshwater that could have re-entered the groundwater instead goes out to sea. When impervious surfaces cover 10% or more of a watershed's land area, the force and volume of runoff flow erodes stream banks and destroys habitat. Eventually, meandering and fish-filled streams become eroded gullies devoid of fish, subject to flash flooding and requiring frequent stabilization due to washouts.

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