Basin 10: Ottauquechee River & Black River (2012)
Basin 10 consists of two major watersheds in southeastern Vermont - the Ottauquechee River watershed and the Black River watershed. The Ottauquechee River has a mainstem length of 38 miles and drains an area of 223 square miles and the Black River, with a mainstem length of 40 miles, drains an area of 202 square miles. There are 19 lakes and ponds in the Basin that are 20 acres or larger covering approximately 1,610 acres. The North Springfield Reservoir, North Hartland Reservoir, Echo Lake, Lake Rescue, Lake Ninevah, and Woodward Reservoir are the largest bodies of water in Basin 10, each being at least 100 acres in size. The Basin is currently 93.8% undeveloped land while only 6.2% is built. One of the most difficult challenges is due to historical settlement patterns where a large amount of the developed land is in the valleys and along the waterways. The land most impacted by development is the same land most critical to water quality and aquatic habitat condition.
Tropical Storm Irene concentrated six to ten inches of rain on the narrow river valleys of Basin 10. With soils already saturated from a wet August, the rivers quickly filled to capacity and rose into and beyond their recognized floodplains. With so much standing in their paths, the massive energy ripped out roads, bridges, culverts, and buildings. While all areas of Vermont experienced the storm, Basin 10 is one of the hardest hit areas in the state. The Ottauquechee River discharged over 4000 cubic feet per second (cfs) of water at North Hartland, over ten times its normal flow rate. Similarly, the Black River at North Springfield reached 4000 cfs, thirteen times greater than normal. We can expect to see the intensity and extensiveness of these storms repeated in the future with greater frequency as Vermont’s climate warms.
The most pressing need identified in the TBP was the need for riparian buffers. It is clearly understood that the lack of buffers is a major cause of water quality and habitat problems in the Basin, and that the simplest, most efficient and most cost effective way to improve and protect surface water quality is to implement coordinated buffer improvements throughout the Basin.
Of the nine waters known to be in need of further assessment, seven have sediment as the suspected pollutant. Silt and sediment are by far the most visible causes of water quality problems noted and impact over thirty miles of river and 132 lake acres. Six impacts from flow alteration at the eighty-nine dams cause stress to rivers and streams. Forty-two dams are in use for hydroelectric power generation, flood control, recreational lake impoundments, water supply reservoirs, and other purposes. Many of the remaining dams, however, are obsolete and serve no current purpose. Their presence in rivers and streams blocks aquatic organism passage, prevents sediment from passing downstream, increases water temperature, and causes disequilibrium in the ecological function of the river system. These pollutants - along with pathogens and excess nutrients - are entering rivers from land development, road runoff, removal of riparian vegetation, and a number of other sources. Basin lakes face contamination and threats from atmospheric deposition of mercury, metals, and acid rain, as well as habitat alterations from varying flow levels. Fortunately there are few impaired waters. These include waters impacted by stormwater runoff from resort development, municipal combined sewer overflows and wastewater treatment facilities, and landfill runoff. There is even one successful removal of a stream from the impaired waters list. Soapstone Brook in Ludlow was recently delisted following diligent stormwater management practice implementation in the watershed.