Locating Waste Management System Sites Using GIS Technology Steve Starrett Assistant Professor, Civil Engg. Dept., Kansas State University, Manhattan, KS, USA Omar Itani Formerly GRA, Civil Engg. Dept., Kansas State University, KS, USA Hugo Davalos GRA, Civil Engg. Dept., Kansas State University, Manhattan, KS, USA Yacoub Najjar Associate Professor, Civil Engg. Dept., Kansas State University, Manhattan, KS, USA Lakshmi Reddi Professor and Head, Civil Engg. Dept., Kansas State University, Manhattan, KS 66502

ABSTRACT

Location of waste management systems is a factor affecting groundwater quality. Leakage from landfills and lagoons usually contain significant amounts of contaminants such as ammonia, nitrate, chloride and metals. These contaminants may reach aquifers and degrade the water resource such that it becomes hazardous to human health. This work is an example of how to determine acceptable areas for waste systems based on information of land use from Geographic Information Systems (GIS), hydraulic conductivity of soils and aquifer depth below the surface. The Equus Beds was the study site. The aquifer provides 50% of the water for municipal consumption for the city of Wichita, Hutchinson and towns in Reno, McPherson, Harvey and Sedgwick counties in Kansas. Also it provides water for crop developing and cattle raising as well as industrial water for private high water consumption companies. In this project we have developed maps assigning levels of contamination risk of aquifer for land zones based on characteristics of the soil such as hydraulic conductivity and aquifer depth. The assumptions, and initial and boundary conditions to calculate contaminant travel time through soil were: the system consisted of two homogeneous layers, the clay liner above and the natural soil underneath; the head above the system is constant; the seepage is vertical and governed by Darcy’s Law. The calculation of travel times was made using the data of hydraulic conductivity and aquifer depth as reference. The scheme of the problem was set up as two layers: compacted clay liner (hydraulic conductivity 10^-7 cm/sec), and natural soil in which permeability values were determined from data provided by the Equus Aquifer Management District 2. After calculating the leachate travel time at hundreds of locations using the MS Excel database, risk levels of low, medium and high were assigned to those nodes. The remaining areas on the Land Use map satisfy the condition that they are at least 5 miles away from rivers, lakes and residential areas. To suggest final landfill locations, a distance of 20 miles from city centers was used to decrease transportation costs. Five percent of the studied area was determined acceptable for large waste systems.

KEYWORDS: Site characterization, GIS, waste management sites

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