Watershed Retrofit and Management Evaluation for Urban Stormwater Management Systems in North Carolina

Abstract

: In response to water quality concerns in the Jordan Lake Reservoir and state and federal mandates, several cities in North Carolina are being required for the first time to reduce nutrient loads in stormwater from previously developed lands; that is, install retrofits. It is anticipated that similar requirements will become necessary for other urban areas in North Carolina. The goal of this study is to evaluate the feasibility of alternative approaches to stormwater management for existing developments within North Carolina cities. Geographic coverage of the study included a portion of the New Hope Creek watershed, located within the City of Durham in central North Carolina. The watershed was analyzed to identify potential retrofit opportunities that could be implemented to reduce pollutant loadings entering New Hope Creek and, ultimately, Jordan Lake. Current pollutant loadings generated by the watershed, as well as reductions in annual loadings of total suspended solids, total nitrogen and total phosphorus that could be achieved by implementing the identified retrofits, were estimated. Trends and relationships between land use type and the quantity and type of retrofit opportunities were identified and conclusions were drawn as to the most appropriate types of retrofits for certain land uses.

Comparing Urban Impervious Surface Identification Using Landsat and High Resolution Aerial Photography

“…Conversion to urban land-losses of agricultural and forested lands, coupled with increasing impervious surface cover-has direct effects on natural temperature regulation [4,5] and alters the hydrologic cycle [5][6][7]. Decreasing vegetative cover and increasing impervious surface cover alters thermal processes in urban regions, thus creating warmer temperature regimes relative to rural areas (urban heat island effect) [5,8,9].…”

“…Decreasing vegetative cover and increasing impervious surface cover alters thermal processes in urban regions, thus creating warmer temperature regimes relative to rural areas (urban heat island effect) [5,8,9]. Alteration of the hydrologic cycle represents the most significant urban water quality issue present today [5,6,10] because stormwater runoff from impervious surfaces creates water quality problems including higher water temperatures and elevated levels of contaminants in surface waters [5,11]. A better understanding of such impacts is required to effectively address these adverse issues [5,10,12].…”

Particle size distribution predicts particulate phosphorus removal

“…Most PP flux in the Piedmont occurs during storms, which dominates the annual P watershed loading. In the North Carolina Piedmont, stormwater BMP’s are often utilized for new development (Gagrani et al 2014 ) and as a retrofit for existing development (DeBusk et al 2010 ). Stream restoration projects often include floodplain reconnection to enhance P sedimentation of PP loads during storm events (Richardson et al 2011 ).…”

Land Use/Land Cover Monitoring and Geospatial Technologies: An Overview

“…These effects, combined with associated decreases in vegetative cover, result in significant local hydrologic modifications [7][8][9] and habitat destruction [10]. Hydrologic modifications represent the most significant water quality and quantity issues present today [7,9,11].…”

“…These effects, combined with associated decreases in vegetative cover, result in significant local hydrologic modifications [7][8][9] and habitat destruction [10]. Hydrologic modifications represent the most significant water quality and quantity issues present today [7,9,11]. Stormwater runoff from impervious surfaces in urban areas degrades water quality through higher water temperatures, increased runoff volume and rate, and elevated levels of contaminants in surface waters [8,9,12,13]-effects which extend well beyond specific urban regions, vitiating downstream waterbodies [14].…”