Evaluation of groundwater recharge at Mafraq wastewater treatment plant catchment area using SCS–curve number method : a case study eastern Badia Jordan

Abstract EN

This study deals with the calculation of the groundwater recharge at Mafraq wastewater Treatment plant catchment area.

The groundwater recharge is the annual total quantity of water, which infiltrates from the ground surface to the aquifer.

It is expressed as the annual recharge rate (mm/year), evaluated on the basis of field measurements and derived from the water balance equation, or estimated with the help of aerial photographs or satellite imagery.

The amount and quality of recharge significantly affects the physical and chemical processes in the soil-rock-groundwater system.

The greater the recharge, the greater the contamination potential to the groundwater.

It may lead to leaching and transporting contaminants from the ground surface to the water table.

In the present research paper, the water balance equation was applied to calculate the groundwater recharge in the study area.

This equation was used to perform the water balance on daily basis for each storm event occurred in wet, normal and dry water year condition.

Rainfall is usually concentrated between December and March; in this period, rainfall duration is long and evaporation is low, so that it can be concluded that the recharge occurs mostly during this period.

The rainfall was the only measured parameter in the study area; therefore, a daily rainfall and initial abstraction were calculated from three rainfall stations using the SCS-curve number method for each storm during a specific year.

The potential evaporation was computed using ccurred in three different water years (wet, normal and dry).

The average annual rainfall in the catchment area varied from about 100 mm southeast to more than 250mm north and northwest of the catchment area.

The average annual rainfall volume was about 33.58 MCM, runoff volume was around 2.49 MCM (7.41 % of rainfall) and the calculated evaporation volume was about 30.46 MCM, (90.7% of rainfall).

The calculated average annual recharge to the upper aquifer ranged between 0.058 MCM (0.30 % of the annual rainfall) and 2.84 MCM (6.85 % of the annual rainfall).