Water Resources Exam 1

Source Water

Water sourced for application

Source Water Applications

1. drinking

2. natural ecosystem (fish, plants, birds)

3. agriculture (irrigation)

4. Industry

5. Power Plants (e-)

6. recreation (boating, fishing)

Source Water Types

1. Natural (River)

2. Engineered (Reservoir)

Estimated World Water Quantities

96.5% non-drinkable oceans

0.3% drinkable surface water

30% Drinkable ground water

Factors that affect selection of source water

1. availability

   a. quantity, V & Q

   b. location (cost)

2. Quality (cost)

3. Development (cost)

4. Rights/law/regulations

   a. Water Rights

Water Budget for Usable Source -River

Q(river)> Q(Town) , V(river) ac-ft > V(town) ac-ft

How to evaluate a river source water

1. collect data

2. water budget

3. determine total amount of water as a volume that flows during a period of time

4. determine total amount of water as a volume being used during that same time period

How to calculate reservoir as a source water?

1. evaluate each individual flow as a volume

2. sum each flow over the same time period

3. calculate change in storage with water budget

4. do a cumulative mass analysis (delta S)

   usually need historical data over time

How to calculate reservoir change in storage volume

Surface area x change in height

How to calculate reservoir change in volume in

Q in x time

How to calculate reservoir change in volume out

Q out x time

How to calculate reservoir groundwater change

Q gw x t

How to calculate reservoir precipitation volume

total inches of precipitation x surface area

How to calculate reservoir evaporation volume

total inches of evaporation x surface area

What is a reservoir

place to store water

hydraulic structure

fills in wet conditions, withdraws water when needed to support community

can be used for recreational purposes

historically surface water but can be groundwater

What does change in storage actually mean

change in height of water of reservoir

What is a drought

dryness, how much rain we are not receiving

a duration

How to design a reservoir

1. if built into a river, confirm that river is a usable source water

2. set up reservoir

3. determine all of the flow data

4. do a reservoir water budget for each year

5. do a cumulative mass analysis (delta s over time)

   1. plot data over time, positive chronological order

   2. identify drought trends in data

6. start of drought is peak in data, next subsequent lowest peak is end of drought

7. Reservoir volume= volume start of drought - volume end of drought

   if a drought is in data set there will be and has been a drought before

Where is groundwater stored?

Aquifers= water in the ground in such abundance that is an be used as a source water

porous material

How to find groundwater?

1. do a water budget

2. storage change measured not equal to calculated = ground water influence

3. drill well, need multiple wells to know extent of flow

How to calculate groundwater flow (confined and unconfined)

Darcy’s Law using hydraulic conductivity table, modeled as a reservoir

Kinds of aquifers

1. unconfined= water table not confined by rock on top but must be confined on bottom

2. confined=water table confined both top and bottom

How to verify GW is usable source?

Pump study

1. drill well

2. add a pump

3. pump the water out and observe how the GW responds

   usually with a production well which has a large diameter

Velocimeter

Parameter found: V

Comments: expensive, need minimum velocity to operate

ADV

Parameter found: V

Comments: expensive, produced great data like sonar/radar, 3D data

Weir

Parameter found: Q

Comments: inexpensive, simple, limited to smaller channels, must occupy entire channel width

Orifice

Parameter found: Q

Comments: inexpensive, simple, limited to smaller channels

Sluice Gate

Parameter found: Q

Comments: OCF, specific energy, fluid mechanics fundamentals, must occupy entire channel width

Float Method

Parameter found: V

Comments: simple, good for slow moving waters

Parshall Flume

Parameter found: Q

Comments: simple measurement, works in dirty/turbid waters, need only the water depth, must occupy entire channel width

USGS Gauge Data

Parameter found: Q

Comments: field measurements, online database

What needs to be measured for velocity parameters

cross-sectional area, more complicated in natural unsymmetric areas

Accuracy in increasing order:

1. 1 point method

2. 2 point method

3. integration method (multiple depths/ points)

How does USGS collect data

Gage stations to measure water depth at a location

What makes water potable?

1. water safe to drink

2. aesthetically pleasing (no odor or color)

3. non-damaging/ corrosive

Parts of a potable water system

1. source

2. pump

3. drinking water treatment plant

4. storage

5. fire hydrants

6. series to loop

7. parallel pipes

What aspects of potable water system are conveyance?

source to drinking water treatment plant

What aspects of potable water system are distribution system?

anything after drinking water treatment plant

T/F potable water systems have multiple flows for the same system?

T

T/F all water systems have loss/leaks

T (10-15%)

How to determine how much water (Q) is needed?

Q directly related to population

Flows are normalized to gallons per capita day

flow study conducted to determine how much water used divided by population

Flow Factor average across USA

157 gpcd

How to measure Qave, yr

Flow factor x population

Trends for potable flow cycle

peaks in the summer (max daily flow), lowest in winter

related to human activity

What is required capacity

design flow/max daily in reference to flow rate

How to calculate Qdesign

Flow Factor (157 gpcd) x peak factor from Table 1.1

How to calculate design flow for potable water system given data

1. Find Design life/period of structure

2. Pick a design life year in the range

3. find the population at that time

4. Use Qdesign equation

What conveyance structure is usually used

pipe line

Why is OCF not ideal for conveyance

risk of contamination after water has been treated due to open channel

Where are pipelines are why

buried underground to prevent freezing and avoid taking up space/getting in the way

Operating Pressure values

Pmin= 20 psi

Pmax=125-350 psi

Ptarget=40-75 psi

What pipe materials are usually used

DIP (ductile iron pipe) or plastic

Pipe Sizing

4” - 20” in 2” increments

24”-48” in 6” increments

Pipe Velocity values

Vmax= 10 fps

avoid 0 fps bc of bacterial growth, add a loop at end of system

Vtarget= 2-5 fps

What must be accounted for in Qdesign for distribution pipes

Fire demand (QNFF)

How to design a potable pipeline

1. select a material

2. Use flow equation Q=VA

3. assume a flow rate in target range (2-5 fps)

4. Use given data on target flow rate (in cfs) set equal to chosen velocity x area of pipe equation (pi/4 D²)

5. Round answer to an actual pipe size

6. check velocity with that pipe diameter