National Park Service

Northeast Temperate Network (NETN)

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Water is a ubiquitous chemical substance that is composed of hydrogen and oxygen and is vital for all known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Water on Earth moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Importance & Issues

Information about water quantity is necessary because water quantity determines the physical extent and volume of aquatic habitat within the park. Numerous factors affect water quantity, including precipitation, evapotranspiration, water withdrawals, and ground water recharge. Hydrologic conditions are extremely important for wetland structure and function. Hydrology affects most abiotic factors, which in turn affect the biotic condition of the wetland. Without basic hydrologic information, it is not possible to interpret the condition of any wetland resources and this is therefore a high priority for wetland monitoring. Water quantity in lakes, ponds and streams will be measured in NETN parks. Protocol development will be based on existing standards, techniques, and sampling designs developed by the U.S. Geological Survey (Rantz et al. 1982).

Monitoring Objectives

  • The overall objective is to monitor the status and trends of NETN aquatic resources, to assess changes in ecological integrity and the impacts of key stressors, and to guide management decisions affecting those resources. The two specific objectives of this program and the questions that frame these general monitoring objectives are:

    • Detect changes over time in the status of physical, chemical, or biological attributes of the freshwater resources in NETN parks that are outside the range of natural variability.
    • Ensure the early detection of aquatic invasive plants in the freshwater resources of NETN parks and alert park and state environmental managers of any new incidences of aquatic invasive species to facilitate a rapid response.


Measures of water quantity are necessary for monitoring the physical status of the freshwater ecosystems, and are fundamental to the interpretation of water-chemistry measures. Measures include lake levels and streamflows (partial record streamflow- gaging stations and continuous-record streamflow- gaging stations).


Last Updated: December 30, 2016 Contact Webmaster