Williston

Hydrology

The Town of Williston is largely defined by hydrologic processes that occurred over 10,000 years ago and persist in the landscape today. Bounded to the north by the Winooski River and to the west by the Muddy Brook, the Town of Williston’s identity is inherently connected to these waterbodies. The headwaters of Allen Brook begins at Mud Pond in the center of town and flows northwest to meet Muddy Brook before its confluence with the Winooski River, serving to bisect the Town. Sucker Brook, a major tributary of Muddy Brook, flows through the southwest portion of the community. Williston’s landscape is made up of several watersheds which drain into the Town’s major surface waters {See Map 1: Williston Surface Waters}. Williston’s hydrology is not limited to these prominent surface waters. While not entirely within the town’s boundary, Lake Iroquois in the southeastern point of the Town is an important resource for wildlife as well as residents from several surrounding towns. Consider also the abundance of forested wetlands, emergent marshes, vernal pools, and groundwater flowing beneath the earth’s surface and the important role they play in landscape processes. These resources serve several functions critical to the organisms that live within the watersheds which makeup Williston.

Within Williston there are a number of hydrologic resources that protect and impact the surrounding lands, specifically lowland wetlands and forested floodplain wetlands, intact riparian zones and streams. Wetlands are nature’s sponges; they provide many functions and services within a watershed, including: pollutant removal and retention, flood water attenuation, groundwater recharge and discharge, stream and shoreline protection, wildlife habitat and recreation. Urban and suburban wetlands can improve water quality by intercepting surface runoff and removing sediments, nutrients, pesticides, metals and other pollutants that originate from land use activities and overflow from impervious surfaces. Surface waters such as the brooks and streams are conduits for headwaters streams and springs located throughout Williston. These surface waters also function as fisheries habitat and are valuable for recreation like bird watching, canoeing, and fishing. The variety of functions served by the hydrologic features within Williston greatly influence land use patterns and plant and animal diversity.

Fundamental to the existence of patterns on the landscape are the ways in which the layers of the landscape overlap and interact with each other. The Winooski Valley floodplain, composed of sediments recently deposited by the river and glacial lake deposits is a rich agricultural landscape {Refer to the Substrate Maps for more details on soils and former glacial lake levels} . It is no coincidence also that the river valleys serve as transportation corridors with roads and railways constructed on the banks of the Winooski River.

As with soils, the presence and type of vegetation, depends on the hydrologic features as much as the pattern and quality of the resource depends on the vegetation. Wetlands found in Williston are composed of plant communities, which have evolved to thrive in various nutrient settings. Floodplain forest communities, found along the Winooski River and larger streams, are home to diverse and often uncommon plant species because of the rich, well-drained soils and varying water levels found there. These water features also act as habitat and corridors for wildlife. The existence of several aquatic species depends on the proper function and quality of the surface waters in Williston. While this analysis was conducted for the Town of Williston, it is important to understand that the patterns on the landscape extend well beyond the Town’s boundaries. The function and quality of hydrology in the Town are impacted by influences upstream and conversely influence hydrologic processes downstream.