Water quality is a fundamental indicator of the impacts from coastal watersheds and the health of estuarine ecosystems. Good water quality affects coastal habitat quality and human communities that rely on estuaries for recreation and livelihoods. Surface water, canopy cover over coastal streams, quality and quantity of ground water, and estuarine water quality represent coastal hydrologic processes that influence spawning and nursery habitats for fisheries, regional and international biodiversity, water sources for household and agricultural uses, and the quality of recreational opportunities in coastal habitats.
Water quality parameters such as clarity, oxygen content, nutrient concentration, temperature, sedimentation, pH, salinity and others all have profound impacts on natural and human communities in coastal ecosystems. Land use practices and climate change affect these parameters and have had dramatic impacts on natural and human communities. Water temperature increases and pH changes associated with climate change are devastating to coral communities. Eutrophication in coastal areas is linked to elevated concentrations of nutrients, reduced oxygen and increased temperatures in estuaries. Agricultural practices in California, for example, have polluted ground water, impacting drinking supplies of some communities. Aquifer withdrawal in Puerto Rico from agricultural practices has modified the ground water table, which in turn has impacted mangrove growth.
The reserves are addressing water quality through intensive abiotic monitoring of estuarine habitats through the System-Wide Monitoring Program, working with farmers to develop and monitor best management practices from agriculture, monitoring the impacts of canopy cover on salmon habitats, addressing sedimentation impacts into coastal streams by working with adjacent land owners and evaluating land use impacts through tools such as the Non-Point Source Pollution, Erosion and Control (NSPECT ) tool.