Understanding the spatial distribution of hydrologic sensitive areas in the landscape using soil topographic index approach

Abstract

Maintaining healthy watershed is pivotal to ensure sustainability in water resources thereby improving the carrying capacity of the earth. Understanding and identifying the spatial variability of hydrologically sensitive areas (HSAs) in a watershed is an important step to prioritizing the landscape to maintain water sustainability with limited resources. A spatial technique known as Soil Topographic Index (STI) was used to identify HSAs in the landscape. This study was conducted in Clinton and Tewksbury Townships in New Jersey, United States. Three different scenarios (STI>=9, STI>=10, and STI>=11) were conducted to understand the spatial distribution of HSAs in the watershed. The following conclusions were derived from this study. Firstly, a more detail representation of HSAs in the watershed was observed when applying the STI technique with a fine scale light detection and ranging (LiDAR) digitial elevation model. Secondly, all three scenarios consistently identified perennial stream corridors as HSAs; therefore, it is important to protect perennial stream corridors through implementation of various land use controls. Thirdly, this study analyzes the land use pattern of HSAs under the three scenarios and identifies the HSAs for high intensity land uses such as agriculture and urban to be the high priority locations for implementing best management practices for water quality improvements. The procedures developed in this study can be applied to watersheds in other parts of the world with similar physiographic characteristics.