Nonpoint source pollution and diadromous fish restoration: An analysis of coastal watershed management strategies and their effectiveness

Abstract

Human development has had damaging effects on coastal watersheds and estuarine environments worldwide. This paper considers the impacts of nonpoint source pollution (NPS) on these environments. Urbanization and agricultural practices have contributed significantly to the rising levels of NPS in these watersheds. Meanwhile, human development has also removed much of the natural riparian buffers that prevent NPS from entering bodies of water. As a result, water quality has decreased in areas where urban and agricultural development is present. In turn, this decrease in water quality has contributed to the decline of diadromous fish populations. These issues (NPS increases, water quality decreases and diadromous fish population declines) are investigated in the Merriland Branch Littler River watershed (MBLR) (located in southern Maine, USA) as well as several other coastal watersheds described by the scientific literature to face similar issues. Comparisons of the management approaches and actions employed in these watersheds are made to facilitate the development of a more comprehensive and highly integrated management framework. This management framework, referred to as the Precautionary Ecosystem Based Best Management (PEBBM) framework combines key characteristics of three commonly used coastal management frameworks: Ecosystem Based Management, Best Management Practices and the Precautionary Principle. The PEBBM framework is applied to the MBLR, outlining a basic watershed management plan.