Introduction to Hydrology and Water Resources

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Introduction to Hydrology and Water Resources

• Philip B. Bedient
• Rice University
• Fall, 2005

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Major Hydrologic Processes

• Precipitation (radar or rain gage)
• Evaporation or ET (loss to atmosphere)
• Infiltration (loss to subsurface soils)
• Overland flow (sheet flow toward nearest stream)
• Streamflow (measured flow at stream gage)
• Ground water flow in wells
• Water quality and contaminant transport

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The Hydrologic Cycle
P - I - E - T - RO dS/dt
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Major Hydraulic Issues

• Energy and momentum principles
• Pipe flow and pipe systems
• Open channel flow
• Flood routing in rivers
• Storage discharge relationships
• Well mechanics and pumping systems
• Contaminant transport modeling

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History of Hydrology - 1800s

• Originally dates back to early Roman times
• Studies done on River Seine in Paris
• Darcy and Dupuit laws of ground water - 1850s
• USGS first measured Miss River flow in 1888
• Mannings Eqn - Open Channel Flow - 1889
• U.S. Weather Bureau 1891 (NWS)

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1900s Hydrology

• Early 1900s saw great expansion of water supply
  and flood control dams in the western U.S. - in
  response to Dust Bowl and the Great Depression of
  the 1930s
• U.S. Dept of Agriculture began many hydrologic
  studies
• Sherman unit hydrograph method
• Theis well mechanics (1935)
• Horton infiltration theory 1940s
• Penman (1948) - complete theory of evaporation

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Recent History of Hydrology

• Great urban expansion in 1950s and 60s - led to
  demand for better water supply and prediction
  (after WW II)
• EPA formed in 1970 with a mission to clean up the
  rivers and lakes of America - beginning of
  environmental science and engineering as we know
  it today
• USGS and EPA actively involved in large-scale
  sampling programs at the national level - (i.e.,
  The Woodlands, TX)
• EPA funded development of computer models to
  address major water quality issues in streams and
  lakes, and estuarine bays.

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BEGINS Rainfall on the Basin

• Frontal Activity (Cold, Warm)
• Convective Summer Storms
• Tropical Storms
• Hurricanes

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Hurricanes Fury
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Hurricane Ivan Sep 04

• Ivan spawned tornadoes from northern Florida into
  Georgia and Alabama with 22 deaths reported in
  Florida.
• Waves as high as 50 feet were measured 75 miles
  south of Dauphin Island from 130-150 mph winds.
• Ivans devastating march across the tropics after
  it formed was precisely predicted because a big
  ridge of high pressure steered it
• Created a potential disaster zone of more than
  350 miles across.

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Hurricane Katrina - 100B in Damages and Loss of
Life gt 2000
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Hurricane Katrina - Most Damaging Storm in U.S.
History
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The Watershed or Basin

• Area of land that drains to a single outlet and
  is separated from other watersheds by a drainage
  divide.
• Rainfall that falls in a watershed will generate
  runoff to that watershed outlet.
• Topographic elevation is used to define a
  watershed boundary (land survey or LIDAR)

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Watershed Characteristics

• Size
• Slope
• Shape
• Soil type
• Storage capacity
• Land use / cover

Divide
Reservoir
Natural stream
Urban
Concrete channel
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Guadalupe River Basin, Texas
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Trinity River Basin DEMor Digital Elevation Model
Discrete Space Representation
Continuous Space Representation
Digital Elevation Model 30m cells
River reaches and their watersheds
TNRCC water quality segments and their
watersheds
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• Geographic Information Systems
• Digital data organized with spatial   analysis
  tools from GIS
• Datasets linked to map locations

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Major Computer Advances

• US Army Corps of Engineers Hydrologic Engineering
  Center (HEC) models - 1970s to the present
• EPA in 1970s - Storm Water Mgt Model (SWMM)
• EPA currently supports a suite of advanced models
  for analyzing water quality in streams and lakes
• 1980s - FEMA floodplain mapping and the federal
  flood insurance program - regulate floodplains
• 1990s - advances in GIS Modeling and NEXRAD
  radar, HEC-HMS and HEC-RAS (1995, 1998 releases)

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Water Resources Engineering

• Water Supply Dams and Reservoirs
• Floods and Flood Control - levee systems
• Irrigation and Drought Control
• Water Distribution Systems
• Hydropower Navigation
• Water Quality and Coastal Resources

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Water Resources Engineering Examples of Problems
AGRICULTURE
BIG DAMS
WATER QUALITY
DROUGHT
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Guadalupe River

• The Guadalupe River was one of the
  earliest-explored rivers in Texas
• Named for Our Lady of Guadalupe by Spanish
  explorers in 1689
• The name Guadalupe, or Nuestra Señora de
  Guadalupe, has been applied to the present river
• One of most beautiful in TX

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Guadalupe River Facts

• The Guadalupe River valley artifacts suggest that
  the area has supported human habitation for
  several thousand years.
• The steady flow from the springs that feed the
  Guadalupe and its tributaries have made the river
  an attractive recreational source.
• Major water supply from Canyon Lake
• May become major source for San Antonio - in the
  near future

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Mansfield Dam - Lake Travis

• Mansfield Dam sits across a canyon at Marshall
  Ford on the Colorado River west of Austin, Texas
• Built from 1937 to 1941
• Named in 1941 in honor of U.S. Representative
  J.J. Mansfield
• Created a 50 mile long lake Travis that is
  hundreds of feet deep in lower end

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HARRIS COUNTY WATERSHEDS
White Oak
Addicks
Buffalo
Downtown
Barker
Brays
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Galveston Bay

• Receives runoff from two major river systems
• Subject to serious water quality and fresh water
  issues
• Major port for Galveston and Houston

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Colorado River - Grand Canyon
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Hoover Dam - Colorado River 1935
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• Dam Builders came in 1931 finished in 1935
• The building of the Hoover Dam meant jobs for
  many people (16,000 workers)
• 96 men were killed in industrial accidents while
  building the Dam, dozens of others from heat,
  carbon monoxide poisoning, polluted water, or
  disease

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Hoover Dam Facts

• Hoover Dam is a testimony to a country's ability
  to construct a major engineering project in the
  midst of adverse conditions
• It took less than 5 years, in a harsh and barren
  land, to build the largest dam of its time
• The dam is a National Historic Landmark and has
  been rated by the American Society of Civil
  Engineers as one of America's Seven Modern Civil
  Engineering Wonders

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Glen Canyon Dam - 1965

• The Glen Canyon Dam is one of the last large
  built dams in the United States - Upper Colorado
  River
• Under the Colorado River Storage Project, the
  Glen Canyon Dam and Lake Powell would form the
  primary storage unit for the area
• Created a major environmental fight over large
  dams in west

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Water Resources Problems

• Severe weather impacts - hurricanes trop storms
• Streamflow and major flood devastation
• Overall water supply - local and regional scales
• Water quality impacts on streams, lakes, bays
• Watershed management for urban development
• Irrigation for agricultural areas - GW impacts
• Maintaining delicate aquatic ecosystems
• Water supplies for developing countries

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ROCKY MOUNTAIN HIGH
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Agricultural runoff in California - Return Flows
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Environmental Hydrology

• Surface water supply and delivery systems
  (sewers)
• Ground water for supply, wells, and springs
• Contamination and environmental quality issue
• Lake and Coastal Bay quality studies
• River quality for drinking water and recreation
• Hazardous waste studies for GW contamination
• Waste sources from urban/industrial runoff
• Land use impacts from urban development
• Disaster mitigation and flood control

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New Technology has Revolutionized Hydrology

• High Speed Digital Computation
• Geographical Information Systems (GIS)
• Large Hydrologic and Meteorologic Databases
• GPS and LIDAR methods for ground surveys
• RADAR rainfall estimates from NEXRAD
• Advanced forecasting tools for severe weather and
  
• flood Alert

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Hydrologic Theory

• One of the principal objectives in hydrology is
  to transform rainfall that has fallen over a
  watershed area into flows to be expected in the
  receiving stream.
• Losses must be considered such as infiltration or
  evaporation (long-term)
• Watershed characteristics are important

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Design Rainfalls

• Design Storm from HCFCD and NWS
• Based on Statistical Analysis of Data
• 5, 10, 25, 50, 100 Year Events
• Various Durations

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RADAR Rainfall Estimates

• NEXRAD provides real-time data on a 16 km2 (6
  mi2) grid
• Equivalent to about 21 rain gages in Brays Bayou
  watershed
• Each estimate represents an average rainfall
  amount over the entire 4 x 4 km2 area
• NEXRAD rainfall estimates compare well with point
  rain gage measurements (r2 0.9)

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FAS NEXRAD
Midnight 1 a.m.
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Unit Hydrograph Theory

• The unit hydrograph represents the basin response
  to 1 inch (1 cm) of uniform net rainfall for a
  specified duration.
• Linear method originally devised in 1932.
• Works best for relatively small subareas - in the
  range of 1 to 10 sq miles.
• Several computational methods exist.

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Loss Rate MethodInitial and Uniform Loss Rate
Method

• Initial Amount Lost to Infiltration (in)
• Soil is Saturated.
• Uniform Loss at a Constant Rate (in/hr)

Inches/Hour
Example Initial Loss 0.5 in, Uniform Loss
0.05 in/hr
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Clark Unit Hydrograph (UH) Computation
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NET RF
Multi-Period Storm
UH

• Pg - Inf Net Rainfall
• Adjust UH by Net RF
• Add and Lag UH
• Compute Storm
•    Hydrograph

STORM
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Central Arizona Projectand the Colorado River
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Colorado River

• In Southwestern U.S.
• About 1450 miles in length
• Drains Rocky Mountains west
• Several cities have aqueducts from the Colorado
  River
• Los Angeles - 14 in RF
• San Diego
• Phoenix - 7 in RF
• Tucson

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Colorado River Compact

• 1922 agreement
• Allocates water among seven states
• Divides river into 2 areas
• Lower Basin Nevada, Arizona, California
• Upper Basin Colorado,
• New Mexico, Utah, Wyoming

• Each section receives 7.5 million acre-foot of
  supply

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Colorado Water RightsArizona vs. California

• 1963 Supreme Court ruled Arizona had rights to
  share water of Colorado River
• Settled 25 yr dispute between Arizona and
  California
• Dispute erupted when Arizona wanted to build CAP
• California said Arizona was stealing their water
  apportionment
• Court decision allowed building of CAP

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Colorado River CAP
Colorado River
Hoover Dam
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The Central Arizona Project Aqueduct (CAP)

• 336 mi diversion canal
• Uses dams, tunnels, and pumps to raise the water
  1,247 ft to the desert plain
• Diverts water from Colorado River into central
  and southern Arizona
• Most expensive aqueduct system ever constructed
  in U.S. - 3.6 billion

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Purpose of CAP

• Helps conserve groundwater
• Imports renewable supply of surface water from
  the Colorado River
• Generates power
• Controls flooding
• Controls sedimentation

The Navajo Generating Station in Page, Arizona
supplies power
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Pumping of CAP

• Largest pumping plant at Lake Havasu
• Goes to Buckskin Mountains Tunnel
• 824 ft above lake
• Water flows 7 miles through tunnel to canal

Pumping Plant on the Hayden - Rhodes Aqueduct of
the CAP.
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The Water is Used for

• Nearly 1 million acres agricultural land for
  irrigation
• Municipal water for Arizona
• Phoenix, Tuscon, Scottsdale
• 12 Indian tribes

Ak-Chin Indian tends to a irrigated field
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History of CAP

• Authorized by the Colorado River Basin Project
  Act of 1968
• Construction began in 1973 at Lake Havasu
• Aqueduct completed in 1993
• Dams completed in 1994
• Many Indian distribution systems remain to be
  built
• Require another 10-20 yrs to finish

Lake Havasu
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Fannin-McFarland Reach 1A winds through a
populated area near Apache Junction.

• Check structures regulate the flow