Land use is one of the fundamental components that needs to be looked at consistently for maintaining proper water quality in the watershed. Increasing population growth along with growing economic activities creates enormous pressure on land uses resulting in land use changes. Land use change can have positive or negative impacts on water quality depending on the activity. In general, agricultural and urban lands are known as high intensity land uses (unlimited anthropogenic disturbances) and generally have a negative impact on water quality. On the other hand, conversion to forest and wetland uses are considered low intensity land uses (limited anthropogenic disturbances) and are likely to have positive impacts on water quality.
New Jersey, as one of the most densely populated states in the United States, has experienced significant land use change trending towards urban land uses, which are often associated with degradation of water quality. Need for housing and economic activities forces development of new urban land which degrades water quality in the watershed. Degradation of water quality due to land use change poses a threat to both human as well as aquatic ecosystems in the watershed. Analysis of land use change is critical to future management decisions that will improve water quality in the Raritan.
Pace of urban development has slowed in recent years. Overall trends for increase in urban land cover is at the expense of agricultural land cover and to a lesser degree to wetlands and forest cover. Such changes have a negative impact on water quality as pervious land cover gives way to more impervious surfaces.