GEOG 102 Mod 6 Lab

Ruby McNamee GEOG 102 GEOG 102 Module 6 Lab: Good to the Last Drop How do planners use the water-budget concept to meet community needs? Part A (40 pts) Water-budget variables are presented in Table 1 and the relationship between these variables is shown in Figure 1 below: Table 1: Water budget variables PRECIP Precipitation How much water comes into the area from the atmosphere. POTET Potential evapotranspiration How much water could be evapotranspired by the incoming solar radiation, if there were an unlimited supply of water. ACTET Actual evapotranspiration Water which returns directly to the atmosphere through evaporation or transpiration by plants within the area. STRGE Soil moisture storage Soil moisture water which is resident (stored) the soil. Δ STRGE Change in soil water storage Change in soil moisture storage is water which is added to or removed from the soil. DEFIC Soil moisture deficit There is not enough water in the area to allow for maximum evapotranspiration (POTET). Therefore, there is a "deficit" ... the amount of incoming solar radiation that is "wasted" because there is not enough water (either PRECIP soil moisture (STRG)) in the area to be evapotranspired. SURPL Surplus Water which runs off into streams/rivers and leaves the area. Figure 1: Water-balance equation or viewed another way PRECIP = ACTET + SURPL ± ΔSTRGE (POTET – DEFIC) Calculations (20 pts) 1. [20 pts] Using the data presented in Table 2 below and the water balance equation, complete the remainder of the blanks in the water-balance table. Note that for Kingsport, the soil-moisture storage capacity is 100 mm. Use the numbers that are filled in already for Jan and Jun to help you complete the remaining calculations. You can type directly into the table.

Ruby McNamee GEOG 102 IMPORTANT: DO NOT use the hints in the textbook. For whatever reason they are completely misleading. Instead, use the hints below, refer to the Lab Guidance page, and post on the Q&A Discussion board if you need additional help. Table 2 Kingsport Water Balance (numbers in millimeters) Kingsport Water Balance Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total PRECIP 95 94 98 77 110 93 140 118 54 52 54 103 1,088 POTET 6 7 22 62 102 144 162 141 99 55 10 8 818 PRECIP – POTET 89 87 76 15 8 -51 -22 -23 -45 -3 44 95 --- STRGE 100 100 100 100 100 49 27 4 0 0 0 95 --- Δ STRGE 0 0 0 0 0 -51 -22 -23 -4 0 0 95 --- ACTET 6 7 22 62 102 144 162 141 58 11 10 8 733 DEFIC 0 0 0 0 0 0 0 0 -41 -44 0 0 -85 SURPL 89 87 76 15 8 0 0 0 0 0 44 0 319 1. Analysis (10 pts) 2. [3 pts] With respect to water supply, what occurs during the warm summer months (Jun-Jul- Aug)? What about during the cooler winter months (Dec-Jan-Feb)? - In the warm summer months, water supply decreases heavily, but there is still some. In the cooler winter months, the water supply was full. 3. [2 pts] During what month(s) is flooding most likely? What about drought conditions? - Flooding is most likely during the cool months when the water supply is full. Drought is most likely in the warmer months when the water supply is low or empty. 4. [3 pts] What is the net demand for water in June? After this demand is satisfied in part by soil-moisture utilization, what is the remaining water in soil moisture to begin the month of July? - The net demand for water in June is precip-potet=-51. After this demand is satisfied by soil- moisture utilization, there is a remaining 49 left in storage for the next month. 5. [2 pts] Based on the total PRECIP vs the total POTET and the monthly STRGE values, how would you describe the average soil-moisture conditions in Kingsport over the course of a year? - The Average soil-moisture conditions in Kingsport over a year tend to be good. 6/12 months the water storage is full. 3 of the remaining 6 months contain some storage, though not full. The final 3 months don’t have any water in storage. Only 5/12 months will there be more evaporation than precipitation, meaning less than half of the year it will dip into the water storage. On average, Kingsport has some soil-moisture if not full soil-moisture conditions. Conclude (10 pts) 6. [3 pts] What needs to happen for a water deficit to occur at a location? - For a water deficit to occur, the water storage must already be very low or zero, and PRECIP - POTENT must be a negative value, meaning it is dipping into the already low storage.