EFFECTS OF URBANIZATION ON BASE FLOW OF SELECTED SOUTH‐SHORE STREAMS, LONG ISLAND, NEW YORK¹

Abstract

Hydrograph analysis of six streams on the south shore of Long Island indicates that eastward urbanization during the last three decades has significantly reduced base flow to streams. Before urbanization, roughly 95 percent of total annual stream flow on Long Island was base flow. In urbanized southwestern Nassau County, storm water sewerage, increased impervious surface area, and sanitary sewerage have reduced base flow to 20 percent of total stream flow. In an adjacent urbanized but unsewered area in southeastern Nassau County, base flow has decreased to 84 percent of total annual stream flow. In contrast, base flow in two streams in rural areas has remained virtually constant, averaging roughly 95 percent of total annual flow throughout the 1955‐70 study period. Double‐mass curve analysis of base flow as a percentage of total annual stream flow indicates that (1) changes in stream flow characteristics began in the early 1960's in the sewered area and in the late 1960's in the later urbanized, unsewered area, and (2) a new equilibrium has been established between the streams in the sewered area and the new hydrologic characteristics of their urbanized drainage basins.

Effects of urbanization variables on model parameters for watershed divisions

“…Thus, the hydrographical characteristics of a developed watershed vary in conjunction with the degree of urbanization (Kliment and Matoušková 2009). Previous studies have shown that the affected factors include rainwater loss (Gremillion et al 2000, Cheng et al 2008b, watershed function (Krug 1996, Kang et al 1998, Aronica and Cannarozzo 2000, Cheng and Wang 2002, surface runoff (Boyd et al 1994, Junil et al 1999, Rodriguez et al 2003, runoff volume (Arnell 1982), peak discharge (Huang et al 2008a(Huang et al , 2008b, time to peak (Huang et al 2012) and baseflow (Simmons and Reynolds 1982). However, the hydrological effects of urbanization may be particularly severe in watershed divisions that are vulnerable to the breaking of links in the hydrological cycle.…”

A comprehensive numerical analysis of the hydraulic behavior of a permeable pavement

“…These impacts include higher peak stream flows, which cause channel incision, bank erosion, and increased sediment transport (Trimble, 1997;Whipple et al, 1981). Another consequence of these impervious surfaces is the reduction of infiltration, which lowers groundwater recharge (Rose and Peters, 2001) and potentially also stream base flow (DeWalle et al, 2000;Simmons and Reynolds, 1982). Permeable pavements represent one solution to the problem of increased stormwater runoff and decreased stream water quality.…”

Monitoring of Environmental Impacts and Land-Use Changes in Water Basin Using Geographical Information Systems: Elmalı Basin Case Study

“…Yerleşim alanlarının artması su geçirmeyen zemin oranını artırmakta, yeraltı yağmur sularının süzülme oranının azalmasına dolayısıyla yeraltı su seviyesinin düşmesine neden olmaktadır. Diğer bir ifadeyle, yeraltına sızmanın azalması yerleşim alanlarında akarsuların akım miktarı %95'ten %20 'ye düşmesine neden olmaktadır (Simmons and Reynolds, 1982).…”