Prioritizing Land Conservation to Protect Water Quality in North Carolina's Triangle Region

Abstract

The Triangle is a rapidly urbanizing region in the Piedmont of North Carolina. Excessive run-off of nitrogen, phosphorus, sediment, and other pollutants associated with urban development and poor agricultural practices increasingly threaten the region’s water quality. The Triangle Land Conservancy (TLC), a local land trust, works in this region to safeguard the Triangle’s surface water quality. TLC reduces threats to regions of high quality water by protecting lands along streams because it is broadly understood that protecting land from development is one of the most cost effective ways to preserve nearby areas of high-quality water. The primary goal of this study is to help guide TLC in their strategic conservation planning through the development of a computer-driven site prioritization tool. The tool ranks areas of high water quality value in the Triangle using a GIS-based approach to Multi Criteria Decision Analysis. The tool specifically focuses on identifying areas of existing high water quality value in the Triangle region rather than identifying potential areas for high impact restoration projects. In developing the tool, the following criteria were used to assess locations based on their raw water quality value: 1.) various forms of land use and land cover; 2.) effectiveness of vegetated riparian buffers; 3.) amount of aquatic biodiversity; and 4.) adjacency to conserved lands. The prioritization tool is intended to be user-friendly so that decision makers at TLC can conduct their own prioritization analyses in the future. In response to the reality of scarce funding opportunities available to local land trusts, the tool also permits user flexibility by allowing the user to manipulate the actual prioritization method. Versatility in the prioritization process is incorporated so that TLC can respond to different decision making contexts and funding opportunities while still being strategic in how they protect the Triangle’s water resources. The secondary goal of this study aims to integrate two key components of TLC’s mission, which are to protect water quality and protect natural habitat, in order to synthesize opportunities for TLC to leverage greater conservation benefits through land protection. This component builds upon a prior assessment of natural habitat, which focused on prioritizing areas of high natural habitat value in the Triangle. In order to leverage two parts of TLC’s work, this study identifies effective riparian buffers that connect important habitat patches of high conservation value.