Determination of hydraulic transmissivity in coastal aquifer by optimal estimation of the Qe-T relationship using Kalman filter

Abstract

Background: The knowledge on the management of water as a vital resource to develop agriculture allows having greater effectiveness in its use. Goals: The agricultural activity in the lower part of the Sinaloa Riverdepends on the fresh water of the regional dams and the aquifer. Methods: The use of groundwater represents approximately 15% of the total water used. In the presence of prolonged periods of drought, new wells are drilled without the use of an appropriate guide for farmers on the location of aquifer areas with a greater hydraulic transmissivity with the purpose of exploiting them more rationally. The National Water Commission has registered more than 680 wells on both banks of the Sinaloa River. Results: The information of 205 of these pumping wells for agricultural or domestic use and the specific capacity information was analyzed. Then, 79 out of 205 wells have pumping tests. It is then determined that the objective of this research work was to find the relationship between the specific capacity (Qe) and hydraulic transmissivity (T) data of the study area using the Thiem formula, considering a fixed value of the radius of influence. This hypothetical consideration and the heterogeneities of the aquifer environment add to the T-Qe relationship an additional component, it is determined that it has a normal behavior. Using the Kalman filter it is possible to eliminate or reduce such a component, thus improving the determination of the T-Qe relation of an R-value of 0.95 (without filter) to 0.97 (with filter), for a linear and exponential relationship. Conclusions: The application of a T-Qe estimate allows characterizing the aquifer area, with this procedure a map was obtained on the distribution of T, which will serve as a guide for future exploitations of groundwater in the study area.