drought and water supply issues in
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Drought and Water Supply Issues in . Water Supply Concerns. Increasing demand. Reduced supply - drought. Water Supply – It all Starts Here. The Natural Supply and Demand of Water. Evapotranspiration. Over 50% of precipitation is lost to evapotranspiration. Precipitation. Moisture - PowerPoint PPT PresentationTRANSCRIPT
Drought and Water Supply Issues in
Water Supply Concerns
Reduced supply - droughtIncreasing demand
Water Supply – It all Starts Here
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9
JanFebMarAprMayJunJulAugSepOctNovDec
Inches of Water
The Natural Supply and Demand of Water
Evapotranspiration
Precipitation
Moisture Surplus
MoistureDeficit
Groundwater Recharge
Over 50% of precipitation is lostto evapotranspiration
Unsaturated RockUnsaturated Rock
CapillaryCapillaryWaterWater
WaterWater TableTable
SaturatedSaturatedWaterWater
Saturated RockSaturated Rock(Aquifer)(Aquifer)
What is Groundwater?
SoilSoil
well
An Example of Normal Groundwater Fluctuations During the Year
-65
-60
J F M A M J J A S O N D J
Dep
th (
feet
)
= 1000 to 5000
= 5,000 to 10,000
= 10,000 to 15,000
= > 20,000
= 15,000 to 20,000
Wells, Springs, and Other Private Water Systems
1990 Census data
Wells drilled between 1966-1994Average of ~15,000 new wells each year!
The Added Pressure on Water Resources
Private Water Supplies in PA
0
200000
400000
600000
800000
1000000
Num
ber
1980 1990
Drilled Wells
Dug Well
Other
Total = 899,483 Total = 1,083,087
Water Use Water Use
Septic System
Consumptive Water Use
Non-Consumptive Water Use
Groundwater MiningConsumptive Water Use
TreatmentPlant
Can result from:-removal of water-density of homes
Drought
• Meteorological: based solely on precipitation
• Agricultural: based on soil moisture
• Hydrologic: based on stream flow, groundwater conditions
**Not correlated to air temperature
Drought Measurements
• Precipitation– NWS precipitation stations
• Streamflow– USGS monitoring stations
• Groundwater Levels– 50+ wells throughout state
• Palmer Drought Index– Computed for ten divisions
• Reservoir Storage– Delaware River Basin
Precipitation Data
Stream Flow Monitoring Network
Ground Water Monitoring Network
observed
average
record low
Example of Groundwater Data Available on USGS Web Site
Palmer Drought Index
• Long term hydrologic index• Widely used (and abused)• Water balance method – compares water
input to water demands • Complex, need 30+ years of data• Values range from +6 to –6• Positive number = surplus moisture• Negative number = moisture deficit• Normalized to climate
Historical Palmer Drought Index in Pennsylvania(1930 – 2001)
-6-5-4-3-2-10123456
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20
00
extremeseveremoderate
Drought Susceptibility
• Cisterns (High)• Streams• Ponds• Springs• Shallow Wells• Deep Wells (Low)
Drought Stages
• Watch - warning – emergency• Each stage carries increasingly strict water use
regulations• Need three of five indices to agree on stage• Stage recommended by Emergency Management
Council• Emergency declared by Governor• Enforced by DEP, River Basin Commissions, police• Separate declarations can be made by the River
Basin Commissions to control streamflow
Managing Your Water Supply During Drought
• Obtain your well log if possible– Rock type, depth, yield, depth to water, etc.
• Keep records • Identify alternate sources (private and public)• Monitor your water supply
– depth to water in the well– flow from springs
• Monitor nearby wells and streams on the web?• Hire a consulting hydrogeologist? ($$)• Water conservation!!
Monitoring Wells During Drought
Water Level Recorder
•Allows accurate detection of water level•Can be easily and quickly read•$250 - $1,000
Planning For Your Water Needs
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10
20
30
40
50
60
gallo
ns p
er d
ay
Person Dairy
Cow
Beef
Cow
Hogs Horse Sheep Poultry
(100)
Turkey
(100)
Recommended Flow Rates for Homes(gallons per minute)
Bathrooms
Bedrooms 1 2 3
2 6 10
3 8 12 14
4 10 14 16
5 15 17
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 12000
0 8 16 24 28 32 36 39 42 45 48 50
Flow Rate (gallons per minute)
Peak Use (gallons per day)
Assumes relatively uniform use throughout the day
Flow Rates for Livestock Production
Example
• 600 hogs @ 4 gpd 2,400 gpd• Hose for hydraulic
waste removal (1 hr) 600 gpd• Total 3,000 gpd
• Necessary flow rate 24 gpm
Home Water Use in Pennsylvania
Toilet29%
Shower18%Bath
3%
Washer22%
Faucets16%
Dish Washer3%
Outside7% Other
2%
Water Conservation
• achieved by change in habit or plumbing• voluntary 10% during watch and warning• mandated 15% during drought emergency
– ban on “non-essential” use– always controversial
• water rationing = last resort• agriculture exempt• can be difficult to enforce
Effect of Water Conservation
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5
10
15
20
25
Toilet Washer Shower Faucets Leaks Other Baths Dish
Washer
gallo
ns p
er d
ay
Without Conservation
With Conservation
Normal use = 72Conservation use = 49Total savings = 32%
Low flow toilets
Front-loading Low flow
showerheadaerators
Pennsylvania Water Use - 1995
0
200
400
600
800
1000
1200
1400
1600
1800
mill
ion
gallo
ns p
er d
ay
Commercial Domestic I ndustrial Mining Livestock I rrigation
Consumptive
Non-Consumptive
Pennsylvania Drinking Water Sources - 1995
59%16%
25%
Public – Surface Water
Private – Ground Water
Public – Ground Water
Total Population = 12,071,810
Per capita ~ 60 gpd
U.S. Per Capita Water Use
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400
800
1200
1600
1920 1930 1940 1950 1960 1970 1980 1990 2000
Wat
er U
se (
gp
d)
These numbers are calculated as the total amount of water usedby everyone (residential, industrial, commercial, etc.) users dividedby the total population.
Pennsylvania Water Law
• Much debate over water use during drought• Centered on “reasonable use”• DRBC and SRBC permit of large users
– Registration of 10,000 gpd users– Permitting of 100,000 gpd
• Little protection for existing sources!• Agricultural uses exempt• Several bills introduced to update the “State
Water Plan”
Southeast PA Ground Water Protection AreaPermit for 10,000 gpd for 30 days
Due to Groundwater Mining
Surface Water Laws
• Riparian Rights doctrine– “landowners with property adjacent to or
crossed by a water body have the right to use the water unchanged in quality or quantity”
– i.e. nobody can use the water!
• Reasonable Use doctrine– Allows water to be used as long as other users
are not unreasonably harmed– Reasonable use defined case-by-case– Domestic > Navigation > Other uses
Ground Water Laws
• American Rule – May withdraw water for any “natural and
ordinary” use without regard for neighboring users
– Natural and ordinary = just about anything as long as it is on the property
– Established to promote economic development– Not meant to deal with disputes– Deepest well and biggest pump wins!– No guarantee of future availability
River Basin Commissions
• SRBC and DRBC – Issue permits for surface and groundwater
withdrawal (100,000 gallons per day)– Designate Special Protection Areas– Declare drought emergencies– Develop comprehensive plan for water use – Resolve disputes??
Drought Resources on the Web
• PA DEP drought home page– http://www.dep.state.pa.us/dep/subject/hotopics/drought/
• PA State Climatologist page– http://pasc.met.psu.edu/PA_Climatologist/
• Mid Atlantic River Forecasting Center– http://crab.met.psu.edu/
• Susquehanna River Basin Commission– http://www.srbc.net/
• Delaware River Basin Commission– http://www.nj.gov/drbc/
• National Climatic Data Center– http://lwf.ncdc.noaa.gov/oa/climate/onlineprod/drought/xmgr.html#ds
• NOAA Drought Information Center– http://www.drought.noaa.gov/
• U.S. Geological Survey– http://wwwpah2o.er.usgs.gov/