Every one of us lives within a watershed, whether we live on a rural farm in Pine Plains, a suburban home in the Town of Lagrange, or in an urban apartment complex in the city of Poughkeepsie. Watersheds are tracts of land in which all of the water that falls onto the land (i.e. rain, sleet, snow, etc.) drains into a single outlet, often a stream or river.
A watershed’s boundaries are determined by the locations of drainage divides, or high points in the landscape, often hills and ridgelines. Water that falls onto one side of the divide allows gravity to carry it downslope into one watershed, while water that falls onto the other side of the divide will flow in the opposite direction, downslope, into a different watershed (Figure 1). Watersheds vary in size. A watershed can be a few acres draining into a small pond or thousands of square miles. Larger watersheds can contain an infinite number of smaller watersheds nested within them. These smaller nested watersheds are referred to as a subwatershed. For example, the Espous Creek is nested within the larger Hudson River watershed, and actions taken within the Esopus Creek watershed can affect the lower reaches of the stream/river network. The fundamental components of watersheds are hillslopes and stream channels, and in a typical healthy watershed in the northeastern United States, hillslopes are covered in forest.
A healthy watershed supports thriving aquatic and terrestrial ecosystems. Nutrients like nitrogen and phosphorus are continuously cycled between soils, vegetation, stream water and animals, and the wastes produced by one organism become food for the next. Vegetation, along with underlying bedrock and soils, affects the chemistry of stream water, determining its acidity or alkalinity and the amount of dissolved nutrients available to aquatic organisms. Vegetated hillslopes reduce the amount of sediment washing into streams, and soil organic matter traps heavy metal pollutants before they can enter the water. A wide vegetated buffer alongside the stream is important for a healthy stream (Figure 3).
Stream channels in healthy watersheds display a variety of habitats for aquatic organisms. Shallow, fast-flowing riffles contain gravel and cobble-sized rocks that provide shelter for fish, crayfish, and insect larvae. Bacterial slimes and algae growing on these rocks are food for higher organisms. These bacteria and algae are also critical for capturing nutrients from stream water and making those nutrients available to the aquatic food web. Deeper, slower flowing pools have floors of silt and sand and support burrowing worms and molluscs. Additional flow regimes, such as glides and runs (intermediate in water depth and speed) may also exist.
In unhealthy watersheds, forested slopes have been replaced by pavement or unprotected bare soil, and storm sewers carry rainfall directly to streams (Figure 3). A lack of trees to intercept rainwater increases the total amount of runoff and the speed with which it reaches channels. Impervious surfaces cause streams in urbanized environments to exhibit higher peak flows and more rapid rises and falls of water level, a condition known as “flashy” behavior. Increased peak discharge leads to a greater frequency of flooding, and increased velocity gives the stream greater erosive power.
Clearing of land for construction or agriculture causes destabilization of soils on hillslopes and consequent sediment movement into stream channels. Filled with sediments, streams lose their capacity to carry storm flow and overflow their banks with greater frequency, and fish and other aquatic organisms lose the diversity of habitats they depend on for their survival and reproductive success. Once their watersheds are fully developed, streams become flashier and begin to erode, both deepening and widening their channels. Homeowners living along the stream may notice the channel begin to migrate as the stream strives for a new equilibrium.
In addition to sedimentation, aquatic ecosystems in developed watersheds have to contend with urban toxins. Motor oil, antifreeze, road salt, and other automotive chemicals washing off of paved surfaces shock sensitive aquatic organisms, and fertilizer runoff from lawns promotes the overgrowth of algae that then decays and consumes dissolved oxygen. The lack of trees to shade the stream and runoff from hot parking lots in the warmer months warms the water beyond the capacity of some species to survive . The results are an impoverished ecosystem.
Fortunately, scientific studies published in the last two decades have pointed the way toward minimizing the impact of development on streams. From the construction of rain gardens that allow runoff from impervious surfaces to infiltrate into soils to clustered development and the maintenance of healthy riparian buffers, there are many steps we can take to reduce or even avoid the unhealthy watershed scenario.
Most people believe that water pollution is caused only by pipes dumping toxic industrial waste into a river. But this type of pollution, called point source pollution, has largely been controlled in waterways by legislation such as the Clean Water Act. Point source pollution enters waterbodies from a known source, by flowing directly out of a conveyance (pipe or storm sewer), and are subject to federal permit requirements. The Clean Water Act places restrictions on how much and what kind of pollutants industries can dispose of in rivers and lakes. While this has not eliminated industrial or domestic waste from entering waterways completely, it has reduced what once was our biggest source of water pollution.
Another common assumption is that waste dumped into the storm sewer is treated at a waste water treatment plant. Sanitary sewers collect wastewater from homes and businesses and treat it before discharging it into a river or stream. Storm sewers, on the other hand, are usually a direct connection to a municipality’s waterways. Anything dumped into a storm grate or gutter discharges - untreated - to a stream or lake at an outfall. Each outfall is considered to be a point source.
A large percentage of water pollution does not come from a single point, but rather many diverse sources - this is called non-point source pollution. As water from rainfall or snowmelt moves through the soil, it carries pollutants from various land uses and deposits them into streams, lakes, and wetlands. Atmospheric deposition (acid rain) and hydrologic modification (dams and control structures) are also considered to be nonpoint source pollutants.
Waterbodies in New York State are regulated under Article 15 (Use and Protection of Waters) and Article 17 (Water Pollution Control) of the Environmental Conservation Law. Under these laws, a permit is required to disturb a protected stream, its bed or banks, or to remove sand, gravel, or other material from its bed or banks. Stream banks are defined as 50 feet from the mean high water mark, with some exceptions.
Water Quality Classifications and Standards of Quality and Purity are defined in the NYS Water Quality Regulations (6NYCRR), Parts 700-705. A protected stream is any stream classified as C(t) or higher, as defined in the table below: Water Quality Classifications and Standards of Quality and Purity (Source: NYSDEC.)
The NYS Water Quality Classifications are based on the best use of the water body. The NYSDEC’s Priority Waterbody List (PWL) was developed to address those waterbodies that do not meet their intended uses due to various pollution sources. Here you will find more information on listed waterbodies within Dutchess County.
The State of New York also has a program, approved by the USEPA that is broader in scope than the requirements of the Clean Water Act. The State Pollution Discharge Elimination System not only regulates wastewater and stormwater discharges to surface waters but also controls point source pollution to groundwater. Under Article 17 (Water Pollution Control) of the Environmental Conservation Law (ECL), the SPDES permit program is designed to eliminate the pollution of New York waters and maintain the highest quality of water possible, consistent with public health, public enjoyment of the resource, protection and propagation of fish and wildlife, and industrial development in the state (see NYSDEC).
Regulated activities under the program include construction or use of an outlet or discharge pipe that discharges wastewater into the surface waters or ground waters of the state. Additionally, construction or operation of a disposal system such as a sewage treatment plant, and discharge of stormwater require a SPDES permit. Permits are required for discharges of more than 1,000 gallons per day to surface and groundwaters. Discharges to groundwater containing sewage, non-sewage or non-industrial wastes fewer than 1,000 gallons per day require approval from city, county or state health departments.
A federal regulation, commonly known as Stormwater Phase II, requires permits for stormwater discharges from Municipal Separate Storm Sewer Systems (MS4s) in urbanized areas and for construction activities disturbing one or more acres. To implement the law, the New York State Department of Environmental Conservation has issued two general permits, one for MS4s in urbanized areas and one for construction activities. The permits are also part of the State Pollutant Discharge Elimination System (SPDES).
Everything in a watershed is interconnected: watershed boundaries do not coincide with political boundaries, therefore the actions that occur upstream can have as much of an impact on a downstream municipality’s land and water resources as those actions carried out locally. Watershed management is a holistic approach to protecting water quality by taking into account the entire watershed system, from uplands and headwaters, to floodplains, wetlands and river channels. It encompasses all activities aimed at identifying sources and minimizing contaminants to a waterbody from its watershed. Watershed management can include utilizing the following practices to protect and improve water quality and other natural resources within a watershed:
A watershed management plan identifies problems and threats to water resources and develops a framework to address those issues within a specific watershed. It is useful as both a process and a tool. A watershed management plan can be a specific document that is developed to guide efforts to control pollution, manage stormwater, and protect and improve local streams. A watershed management plan can also be the written expression of the collaborative agreement among various government entities, other local stakeholders, and citizens that is developed during the planning process.
Several of the watersheds within Dutchess County have extensive Watershed Management Plans or Assessment Documents with recommendations on how to protect and restore the watershed. For more information on any of the following watersheds, also see their information pages.
For more information and resources on how to put together a Watershed Management Plan visit our Resources page.