Task 1: Hydrological Budget The problems in this task will provid...

Task 1: Hydrological Budget
The problems in this task will provide you with experience estimating hydrological budgets (water balance). You are doing a basic accounting of water. The challenge is to make sure all of your units are consistent. In the two problems below, make sure to include equations and all calculations that you perform and describe all assumptions.

a) In the year 2010, a watershed with an area of 2500 km2 received 1200 mm of precipitation. The average flow rate in the river that drains this watershed was 30 m3/s (there is no river that flows into this watershed). Estimate the amount of water lost from the watershed due to evapotranspiration and infiltration to groundwater (combined). Provide your estimates in units of mm/yr. Assume that the storage of water in the area at the beginning and end of the year are equal.

b) A city in a tropical region is supplied by water from a 1250‐ha catchment area. The average water consumption of the community is 50,000 m3 per day. The annual precipitation in this tropical region is 4120 mm. A river with an annual flow of 0.35 m3/s originates in and flows out of the catchment. The net groundwater outflow from the area is equivalent to a 160‐mm depth of water. What is the evapotranspiration loss (in cubic meters per year), which, if exceeded, would cause a shortage of water supply to the community? Again assume that the storage of water in the area at the beginning and end of the year are equal.

Task 2: Precipitation Analysis
This task is designed to give you experience analyzing precipitation data and interpreting the data for policy related decisions. The interior of the state of Ceara in northeastern Brazil has a semi‐arid climate. Rain‐fed agriculture is the norm in Ceara. The monthly rainfall data from 1974 to 2000 for the location are presented in the attached spreadsheet

a) Using this data, plot a time series of annual precipitation for the region. Include a horizontal line that shows the mean annual precipitation. In how many years is the annual precipitation above the mean? How many below?

b) Plot a histogram of the annual precipitation. What does the histogram tell us about how the annual precipitation is distributed?

c) If you are a farmer here, what are your concerns based on these data? How might you manage the water resources under these environmental conditions?