a) Use the following formula to compute the temperature of both Venus and Earth as a simple black body that includes albedo: Environmental Hydrology GGE 303 Name_____________________
Test 1 --- 100 points (show all your work!) Spring 2000
1. (35 pts) The map below (not available on web version) contains the entire watershed of Georges Fork Creek, a small headwater drainage basin in the Wasatch Range of central Utah. The basin immediately above the confluence with Lake Fork Creek covers an area of 1276 acres (43,560 square feet in an acre). Precipitation (water equivalent) averages 21 inches per year (365 days or 3.1536 x 107 seconds). Evapotranspiration accounts for about an 80% loss.
a). Delineate the watershed by carefully drawing a line along all of the divides. (Use the confluence of Lake Fork and Georges Fork as the lowest point).
b). Doing the best job you can with the information given, estimate the long-term average discharge (cubic feet per second) of Georges Fork immediately above the confluence with Lake Fork. (Show your work)
______________ cu. ft / s
c). On the back of this page discuss the uncertainties in your estimate. If you were to measure the discharge and find that it was 0.4 cubic ft / s, how might you explain the difference? What would you need to do to confirm your ideas?
2. (20 pts.) A typical average human being has the following characteristics:
|
total mass |
60 |
kilograms |
|
% of mass as water |
55 |
% |
|
mass of water in body |
33 |
kilograms |
|
average daily water intake |
||
|
tap water |
0.15 |
kilograms per day |
|
water in other fluids |
1.50 |
kilograms per day |
|
free water in foods eaten |
0.60 |
kilograms per day |
|
water derived from oxidation of food |
0.30 |
kilograms per day |
What is the average residence time (in days) of water in a human? ___________ days
3. (25 pts.) a). What was the Younger Dryas event?
b).When did it occur and how long did it last?
c).What region(s) were affected the most?
d). On the back of this page describe how Broecker and Denton explain the origin of the Younger Dryas.
4. (20 pts) Venus is a very hot planet (the average temperature at the surface is about 700° K, compared to Earth's 288° K) surrounded by a dense, thick, and highly reflective atmosphere composed of about 97% CO2. The albedo is about 0.75, or about 2.5 times greater than that of Earth (0.3). Incoming solar radiation for Venus is 2613 watts per square meter, compared to Earth's at 1372 watts per square meter. The Stefan-Boltzmann constant is 5.67 x 10-8 watts per square meter - ° K.
a) Use the following formula to compute the temperature of both Venus and Earth as a simple black body that includes albedo:
Earth _______° K Venus _______° K
b) Although Venus is closer to the sun than Earth and has a larger solar constant, it is "cooler" than the temperature estimated for the earth. Why?
c) Why are the surface temperatures so much higher on Venus?
Hydrology Geol. 342
Test 1
1. (3 pts.) Edmund Halley is pretty well known for Halley's Comet, but not as well known for his work in hydrology. He conducted a hydrological study in the Mediterranean region back around 1700. What did he show?
2. (10 pts.) From what geographical region do most of the world's deep ocean currents originate?
3. (10 pts.). An ice core from Greenland reveals an increasing proportion of 16O with depth in the ice. This suggests that since the beginning of ice deposition......
a. average global temperatures had warmed and CO2 had decreased
b. average global temperatures had warmed and CO2 had increased
c. average global temperatures had cooled and CO2 had decreased
d. average global temperatures had cooled and CO2 had increased
e. not enough information to tell
4. (15 pts.)Briefly explain why reasonably deep lakes in our region undergo a "convective overturn" in the spring.
5. (15 pts.) I have a 1 kilogram capacity "electric" dog water dish that keeps the water from freezing in the winter. The problem is that the dogs sometimes unplug it and the water freezes anyway. If the dish operates at 100 watts (1 watt = 1 Joule/second), what will be the minimum time required to just completely melt the ice? Assume the ice was at -10 oC. and that all the heat is transferred to the water in the dish......none is lost to the surroundings. (The specific heat of ice = 2092 J/kg-oC and the latent heat of fusion = 335 kJ/kg).
6. (17 pts.) A prairie pothole wetland in central ND covers about 10,000 square meters and has an average depth of 0.75 meters down to very low permeability glacial till. There is no surface water in the wetland; only saturated soils that have a porosity of about 0.2. The pothole receives about 0.3 meters of precipitation per year. There is no runoff into or out of the pothole and virtually all the water is lost to evaporation and transpiration. Estimate the residence time (days) of water in the pothole.
residence time = ___________________________
Do you think water residence time differs for various ND prairie pothole wetlands? Explain why. How might this relate to differences in ecology and water quality from one pothole to the next?
7. (20 pts.) Briefly describe the structure and some of the characteristics of the Earth’s atmosphere.
8. (10 pts) Hydrological processes take place over a wide temporal and spatial scale. On the graph shown below plot a point or box that might roughly represent the scales of the following hydrological processes (note that the axes give the log value of length and time)
a. Runoff in English Coulee
b. Runoff in the Red River basin
c. Thunderstorm
d. Accumulation and melting of a snowbank plowed out of Columbia Mall's parking lot
