Doctoral Dissertations

Date of Award

8-1985

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Geography

Major Professor

Theodore H. Schmudde

Committee Members

Edwin H. Hammond, Bruce A. Tschantz, Sidney R. Jumper, Bernard J. Frederick

Abstract

Kingston, Jamaica, is situated on the Liguanea aquifer and draws a substantial portion of its water supply from underground source. The purpose of the study is to estimate the volume of groundwater stored during dry, average, and wet years, as a basis for determining whether additional water can be withdrawn as an alternative to proposed expensive, large-scale, inter-basin water transfer.

The study area includes four lithologic subdivisions of which the Liguanea alluvial surface is the largest. Each subdivision is treated separately because of differences in infiltration and runoff rates as well as subsurface storage capacities. The hydrology of the study area is simulated using the Thornthwaite water balance procedure based on climatic data for 16 stations. The allocation of surplus to either runoff (overland flow, streamflow, gullyflow) or recharge (baseflow or groundwater storage) considers regional differences in lithology, urban build-up, and seasonal rainfall and its intensity.

The simulated volumes of runoff and recharge are tested for validity using observed values of streamflow and change in height of the water table based on well records. Matching observed stream-flow at Gordon Town to simulated runoff for the comparable drainage area for the average year of 1971 shows that the volume of simulated runoff and the volume of observed runoff are in close agreement (less than 5% difference). Likewise the volume of simulated re-charge for the Liguanea aquifer in the dry year of 1977 and the wet year of 1979 and the observed change in volume of groundwater have similarly close agreements.

The close correspondence between simulated and observed runoff and recharge in the study area strongly suggests that the water budget analysis and the procedure for allocating surplus to runoff and recharge used in this study is a workable model of the general hydrology of the study area. The results show that approximately 400 million gallons of water would go to recharge in dry years compared to 9000 million gallons in wet years. The primary recharge area is the northern boundary of the Liguanea alluvial surface. Coefficients based on rainfall totals for each lithologic subdivision and for wet, average, and dry years have been prepared. These coefficients, calibrated to conform to the estimates using the more elaborate procedure of this study, provide a quick way to estimate recharge for any year. Caution, however, should be exercised in applying such coefficients outside the study area where the rainfall and surface conditions may be quite different.

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