A watershed describes an area of land that drains downslope to the lowest point. Water moves through a network of drainage pathways, both underground and on the surface, and these pathways converge into streams and rivers, which become progressively larger (i.e., higher order) as the water moves downstream and the size of the contributing drainage area increases. The connectivity of the stream system is the primary reason for conducting aquatic assessments at the watershed level. Because water moves downstream, any activity that affects the water quality, quantity, or rate of movement at one location can affect locations downstream. Watersheds are widely accepted as an appropriate geographic unit for managing water resources. The condition of a watershed greatly influences the functions and integrity of its wetlands and streams. Land use disturbances in watersheds can have significant negative impacts on wetland or stream morphology, vegetation, flood abatement, water chemistry, and aquatic biota. Watershed-based planning and zoning begins with the notion that the level of impairment of a watershed (e.g., the percent developed lands versus undeveloped forested lands) largely determines the quality of streams and therefore, the attainability of stream protection goals. This, in turn, strongly influences the nature of the stream protection strategy for a given watershed (i.e., the selection of land use standards, stream corridor management plans, implementation of best management practices, and instituting land acquisition or other protection strategies). The extent of forest, in particular, is an important indicator of watershed condition due to its strong association with water quality and as an indicator of the extent of alteration of a watershed due to past human activity. Peer-reviewed scientific literature was reviewed to identify defensible indicators of watershed condition for the Highlands Region. From the suite of indicators identified in the literature, an interdisciplinary team of scientists at the Highlands Council selected the following to evaluate each of the HUC14s of the Highlands Region including: Percent Developed Lands, Percent Habitat Quality, Percent Total Forest, Percent Core Forest, Proportion of Total Forest. Percent Developed Lands is the percentage of a subwatershed that is developed, with developed defined as lands that have been altered for residential and/or commercial use. Developed lands include areas with impervious cover as well as those with non-impervious cover (e.g., lawns, golf courses). Percent developed land is an indicator of watershed impairment (i.e., in general, the higher the percentage, the lower the watershed quality). A negative relationship between developed land use and aquatic habitat integrity exists. The US Geological Survey National Water Quality Assessment study compared aquatic community indicators of selected watersheds to the proportion of urban land use in the watershed. It was found that as natural vegetation communities are replaced by developed land, downstream water quality declines due to combined impacts of point and non-point source pollution and soil erosion. The source of these data is the Land Use Land Cover data set developed by the NJDEP.Habitat Quality represents the percentage of a subwatershed that contains habitat for species of concern including rare, threatened or endangered species. The source of this data is the NJDEP's Endangered and Nongame Species Program (ENSP) Landscape Project. Habitat quality is used as an indicator of the biological diversity of a watershed (i.e., the more habitat that supports a species of concern, the higher the quality of habitat within a watershed). Given the importance of the Act in protecting rare, threatened, and endangered species they are considered to be excellent indicator of watershed protection needs. Often a rare, threatened and endangered species serve as an indicator species and are the first to show the effects of environmental alteration and degradation because they are often sensitive to biological changes within their habitat.Forest Cover provides a reliable indicator of essential ecosystem functions of surface water filtration and groundwater recharge. Connection between forest and water quality has been acknowledged for more than one hundred years, as is evidenced in the 1899 New Jersey State Geologist's Report on the forests of New Jersey. Further, as previously noted, forests are an indicator of the extent of alteration of a watershed due to past human activity. Three distinct forest cover metrics were utilized to characterize watershed condition, as briefly described below: Percent Total Forest is the percentage of a subwatershed that is forested, with forested defined as all mature and successional upland and wetland forested communities (excluding old fields). Percent Core Forest represents the percentage of a subwatershed that contains forest areas greater than 300 feet in distance from an altered edge (i.e., disturbed land). Proportion of Total Forest is the amount of forest cover within a given geographic area. A 3-kilometer search area was used to calculate this metric. The source of these data is the Land Use Land Cover data set developed by the NJDEP.
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