Investigation of Impacts of Urbanization on Base Flow and Recharge Rates, Northeastern Illinois: Summary of Year 2 Activities

Meyer, Scott C.

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https://hdl.handle.net/2142/55237 Copy

Description

Title

Investigation of Impacts of Urbanization on Base Flow and Recharge Rates, Northeastern Illinois: Summary of Year 2 Activities

Author(s)

Meyer, Scott C.

Issue Date

2002

Keyword(s)

groundwater

Geographic Coverage

Illinois

Abstract

Base flow and precipitation data from three urbanized watersheds and three urban watersheds in northeastern Illinois and three rural watersheds in northern Illinois have been explored for impacts of urbanization on base flow and groundwater recharge rates. Spearman rank correlation coefficients suggest the correlation between base flow and precipitation rates in the urban streams has become slightly weaker during the period of urbanization of the northeastern Illinois watersheds. Double-mass curves suggest that the ratio of base flow to precipitation in the urban watersheds has increased during the period of urban growth. Time-series and double-mass plots suggest that, in urban McDonald Creek, the base flow rate increased during urbanization, but these increases were exceeded by increases in the base flow rate in the three rural streams. Time-series plots show that base flow in McDonald Creek increased between the late 1970s and 1998, counter to the decreasing precipitation trend during the period. The results of this study are consistent with a conceptual model in which urbanization leads to contributions of water to stream base flow that are unrelated to precipitation events, such as leakage from water distribution systems or sanitary sewers, or the collective runoff from lawn-watering, car-washing, and similar activities that introduce water to storm sewers during dry periods. The base flow rates that have been determined for these watersheds are of dubious value as indicators of groundwater recharge rates since base flow in the urban streams rates may include a component of runoff. The conclusions of this study may not be widely applicable since only a small number of watersheds having suitable streamflow data are available, and since the period of common record between the urban and rural gages is of short duration.

Publisher

Illinois Groundwater Consortium

Series/Report Name or Number

Proceedings, 12th Annual Illinois Groundwater Consortium Symposium

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/55237

Copyright and License Information

This document is a product of the author and the Illinois Groundwater Consortium, and has been selected and made available by the Illinois State Water Survey and the University Library, University of Illinois at Urbana-Champaign. It is intended for research and educational use, and proper attribution is requested.

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