Lake Michigan Water Resources Study

This paper contains an analysis of withdrawal data for North West Indiana to compute consumptive-use coefficients and to describe monthly variability of withdrawals and consumptive use. Concurrent data were available for most water-use categories from 1990 through 2008. Average monthly water withdrawals are discussed for a variety of water-use categories, and average water use per month is depicted graphically. Water quality analysis is presented and historic water quality data of Northwest Indiana, (Lake, Porter and LaPort Counties) were downloaded from USEPA website and they were examined for the trends in different water quality constituents. Individual station based analysis and regional analysis were conducted using MK Test. Water quality data indicated an improvement trend. Water withdrawals data were analyzed using regression and Artificial Neural Network (ANN) models. The ANN model performed a better forecasting while compared to a linear regression model. For most water-use categories, the summer months were those of highest withdrawal and highest consumptive use. For public supply, average monthly withdrawals ranged from 2,193 million gallons per day (Mgal/d) (February) to 3,092 Mgal/d (July). North West Indiana energy production had large increases in average monthly withdrawals in the summer months (17,551 Mgal/d in February to 26,236 Mgal/d in July, possibly because of increased electricity production in the summer, a need for additional cooling-water withdrawals when intake-water temperature is high, or use of different types of cooling methods during different times of the year. Average industrial withdrawals ranged from 31,553 Mgal/d (February) to 36,934 Mgal/d (August). The North West Indiana irrigation data showed that most withdrawals were in May through October for golf courses, nurseries, and crop irrigation. Miscellaneous water withdrawals ranged from 12.2 Mgal/d (January) to 416.3 Mgal/d (October), commercial facilities that have high water demand in Indiana are medical facilities, schools, amusement facilities, wildlife facilities, large stores, colleges, correctional institutions, and national security facilities. Consumptive use and consumptive-use coefficients were computed by two principal methods in this study: the return-flow and withdrawal method and the winter-base-rate method (WBR). The WBR method was not suitable for the industrial and miscellaneous water-use categories. The RW method was not used for public-supply facilities. The public-supply annual average consumptive-use coefficient derived by use of the WBR methods is 8 percent from 1990 to 2008 for North West Indiana; the summer average consumptive-use coefficient was considerably higher with the amount of 20 percent. The energy production annual consumptive-use coefficient was 13 percent by the WBR method, which increased to 28 percent for summer. In terms of maximum accuracy and minimal uncertainty, use of available withdrawal, return-flow, and consumptive-use data reported by facilities and data estimated from similar facilities are preferable over estimates based on data for a particular water-use category or groups of water-use categories. If monthly withdrawal, return flow, and consumptive use data are few and limited, monthly patterns described in this report may be used as a basis of estimation, but the level of uncertainty may be a greater than for the other estimation methods.