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Question: homework 3 winterwet drainage basin water budget the small map...

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Homework 3- Winterwet Drainage Basin Water Budget The small map on the back of this sheet depicts the Winterwet drainage basin, which has a catchment area of 2500 km2 that is drained by the Winterwet River. The margins of the Winterwet basin are determined from the topographic drainage divides along the higher ground. On one side of a divide, rain water flows into Winterwet basin; on the other side, it flows into an adjacent basin. nterwet area falls in the winter and early spring. Summers are dry starting in mid June. Last year, 112 cm (45 inches) of precipitation fell, including rain and snow Over the course of the year, 60% of the basins input moisture e vaporates evapotranspiration. includes evaporation from plants 10% infiltrates into the ground, joining the ground water and 30% runs off (as runoff into rivers). All of the runoff flows down Winterwet River and into Winterpond Reservoir, which is dammed at the outlet of the basin (see map). Last year, the Winterpond Reservoir operators released downstream 50% of the water that entered the reservoir during the rainy season, thus 50% of the runoff remained stored in the reservoir. The stored water was used to irrigate the local crops of apples, tomatoes and peppermint. Altogether, these crops require 3 cm of irrigation water per week over an irrigation season of 12 weeks, from mid June through August. The total irrigated land area is 1000 km2 The 10% of precipitation that joins the ground water in the winterwet basin enters the winterwet Sand, an unconfined alluvial aquifer with an areal extent of 800 km2 and a porosity of20%. The porosity is the percent of the total volume of the sandstone that is not occupied by rock material itself and is therefore available to store water. It is immaterial to the following questions, but recognize that the water that accumulates in the aquifer within the Winterwet basin drains out down- gradient through the extension of the same aquifer below the Winterwet basin. The basin water budget, as described above, can be represented in the form of the equation, below (Manga, 1997). See whether you can make it add up correctly for the basin described above. Water budget equation (all units volume): PHE+R+G+DS P is preeipitation; E is evapotranspiration: R is runoff Gis ground water recharge; DS is ehange in water storage the Winterwet basin water budget. These questions Please answer the following guestions about are casiest to answer by using a spreadsheet, but a hand caleulator will work OK. Hint: before so make your conversions to the data before starting beginning make a list of all the known data you can retrieve from the reading above. Volumes will be calculated in m (cubic meters) questions. Show your work for all caleulations!!!!! 1) What total volume of precipitation fell within Winterwet basin last year? (Compute this and other water volumes in cubic meters). (2 points) 2) What volume of water evaporates? (2 points) 3a) What volume of water is stored in Winterpond Reservoir before mid-June? (2 points) 3b) What volume of water is available in the Winterpond Re 4a) Whar volume recharges the ground water in the Winterwet Sand aquifer? (2 pts) irrigation? (2 4b) What is the surface area of the pore space in the aquifer? (2 pts) 4c) Assuming that all the recharge is evenly distributed in the pore spaces across the of the aquifer, how much would the water table surface rise with this input of groundwater and is assuming no groundwater flow out of the
wn ueseribed above. uion (ar uhils volume): P E+R+G+ DS P is precipitation; E is evapotranspiration: R is runoff, G is ground water recharge; DS is change in water storage. Please answer the following questions about the Winterwet basin water budget. These questions are easiest to answer by using a spreadsheet, but a hand calculator will work OK. Hint: before beginning make a list of all the known data you can retrieve from the reading above. Volumes will be calculated in m (cubic meters) so make your conversions to the data before starting questions. Show your work for all calculations!!!!! 1) What total volume of precipitation fell within Winterwet basin last year? (Compute this and other water volumes in cubic meters). (2 points) 2) What volume of water evaporates? (2 points) 3a) What volume of water is stored in Winterpond Reservoir before mid-June? (2 points) 3b) What 4a) What volume recharges the ground water in the Winterwet Sand aquifer? (2 pts) 4b) What is the surface area of the pore space in the aquifer? (2 pts) 4c) Assuming that all the recharge is evenly distributed in the pore spaces across the surface area volume of water is available in the Winterpond Reservoir for irrigation? (2 points) of the aquifer, how much would the water table surface rise with this input of groundwater recharge? (This is a simplisitie caleulation and is assuming no groundwater flow out of the aquifer) (2 points) 5a) What volume of Winterpond Reservoir water is needed to irrigate the erops? (2 pts) 5b) Will there be enough available in the reservoir to irrigate the crop (if yes how much excess, if no how much deficit? (2 points)
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