1 Hydrology Let us get started

2 Surface Water Hydrology Definitions: Precipitation: Rain, Sleet, Hail, or Snow Evaporation: Transformation of water from liquid state to vapor state. Transpiration: Water vapor released by plant leaves, similar to breathing by animals and humans by breaking down nutrients to generate energy. You transpire when you run away from a mountain lion, or when you take the final exam.

3 Surface Water Hydrology Surface Runoff: Surface Runoff: The water that runs off over the ground into streams and rivers. Base Flow: Base Flow: The water that seeps up into a stream from groundwater or water springs. Watershed or Basin: Watershed or Basin: Is an area where the precipitation will shed into a stream.

4 Units of Measurement Precipitation: Precipitation: mm/h (millimeter/hour), approximately 1 mm of water is equivalent to 10 mm of snow. How about wet snow in April? Stream Flow: Stream Flow: m 3 /s (cubic meter/second). One m 3 = 1000 liters.

5 Units of Measurement Speed: Speed: m/s (meter/second). You can also use the English System (Ft, Gallon, etc.). I will do my best not to use it because it is dumb, but if you have any questions I will help. You can also use the English System (Ft, Gallon, etc.). I will do my best not to use it because it is dumb, but if you have any questions I will help.

6 Stream Flow Sources: Sources: 1. Direct Runoff 2. Groundwater exfiltration, or also called Base flow (opposite of infiltration)

7 What Happens to a Drop of Rain 1. Some of it will evaporate on the way down, air temperature is a factor. 2. What is left will hit the ground, some will infiltrate, some will be trapped in puddles, and some will runoff to streams and rivers. Is a lake a large puddle?

8 How do Clouds Form? 1. Evaporation: Rain, Snow, Surface water, Lakes, Oceans, etc. 2. Transpiration: Plants, animals, and wild humans.

9 What Causes the Hydrology Cycle? Can you believe it is Solar Energy? Can you believe it is Solar Energy? Solar Energy causes also wind. Wind increases the rate of evaporation, why? If you do not know the answer, ask Mr. Science in class, but be nice. Next we will see the processes.

10 What Causes the Hydrology Cycle? The sun heat evaporates water, also creates differences in temperatures in air masses vertically and horizontally creating wind which will evaporate water. Animals exhale water vapor, plants exhale water vapor after sunset. The warm vapor cloud rises and moves with the wind. It hits a cool front, condensates into small droplets, the droplets get bigger and heavier and fall as rain, snow, or hail, some will evaporate while falling.

11 What Causes the Hydrology Cycle? Some of the precipitation will be trapped in puddles, some will evaporate, some will infiltrate the ground, and some will run off into steams. GoTo the beginning of last slide. Now you learned a new word; GoTo, it is a statement in every programming language, you guessed it, it means go to.

12 The Hydrologic Equation This is not the Monster at the End of this Book! I am scared; Equation! Ok, let’s make it simple. You have a piggy bank, and you put in $10 each day, take out $16 each week, how much money did you store in the bank after 28 days? If you replace the dollars with m 3 of water, and the bank with a stream what will that be? Answer: The Hydrologic Equation.

13 WATER DEMAND To design a water system, we need to know the future water demand, water supply, and per capita daily use. To design a water system, we need to know the future water demand, water supply, and per capita daily use. First, we need to forecast the population, using historical growth data. First, we need to forecast the population, using historical growth data. Population Growth versus Time can fit: Population Growth versus Time can fit: 1. Arithmetic (Linear) Growth 2. Geometric Growth 3. Growth at a declining rate of increase

14 Population Forecast Equations

15 DEFINITIONS P sat Is the saturation population, the maximum population when the growth rate reaches zero in a declining growth rate population. An example of a country with a declining growth rate is China, the population is still growing, but due to the policy of one child per couple, the annual rate of growth is declining. P sat Is the saturation population, the maximum population when the growth rate reaches zero in a declining growth rate population. An example of a country with a declining growth rate is China, the population is still growing, but due to the policy of one child per couple, the annual rate of growth is declining. Ka, Kg, Kd, a, b are assumed constants Ka, Kg, Kd, a, b are assumed constants

16 NOTES Remember, when you calculate P sat, the time intervals between P 0 -P 1, and P 1 -P 2 have to be equal. Remember, when you calculate P sat, the time intervals between P 0 -P 1, and P 1 -P 2 have to be equal. In the Mathematical Logistic Curve Method, Equation 1.8 in the Text, t is the time from P 0 to P t. In the Mathematical Logistic Curve Method, Equation 1.8 in the Text, t is the time from P 0 to P t. Equation 1.19 does not hold if the population is > 10,000 (multiplication by 0) Equation 1.19 does not hold if the population is > 10,000 (multiplication by 0)

17 Solved Problems Hydrology Text, Problem 1.1

18 Problem 1.3a Text

19 Problem 1.5 Problem 1.5

20 Problem 1.7 Problem 1.7

21 1.9a 1.9a

22 1.9b 1.9b

23 1.9b 1.9b

24 1.9b 1.9b