Transcript CE 301 Lecture on Water Resources, Feb 18, 2004

Water Resources Engineering
by David R. Maidment
• The challenges
– floods, droughts, poor water quality
• What we are doing about them
– engineering structures, better planning,
management
• What we study
– Academic Program at UT
Flooding
Manawatu, New Zealand, Feb 17, 2004
http://www.ourregion.co.nz/home.php
Bridges that Work
http://www.ourregion.co.nz/home.php
Bridges that don’t work
Small bridge on a country road is washed away
http://www.ourregion.co.nz/home.php
http://www.tsarp.com/
Most costly urban flood disaster in the history of the United States
Major Highways during Tropical
Storm Allison
I-10 West
I-45 South
http://www.chron.com/content/chronicle/special/01/flood/
Kayaking on US 59, Houston
(Tropical Storm Allison)
http://www.chron.com/content/chronicle/special/01/flood/
Residential Flooding in Tropical
Storm Allison
http://www.chron.com/content/chronicle/special/01/flood/
The Human Cost
Saving the wedding photos
Cleaning out the car
http://www.chron.com/content/chronicle/special/01/flood/
5-day rain total
(Tropical Storm Allison)
Harris County
City of Houston
12-hour rain total
(Tropical Storm Allison)
Extreme Rainfall Statistics
(Tropical Storm Allison)
73,000 houses and apartment
buildings flooded
Watersheds
Stream gaging
station
Watershed = area that drains to
a particular river or stream network
Floodplain maps
(White Oak Bayou, Houston)
What can we do about floods?
• Engineering structures
– Dams and detention ponds to hold back flood
waters
– Increase capacity of streams to carry floods
• Better flood planning
– Create floodplain maps to define at-risk areas
– Restrict building foundations are at least 1 foot
above 100-year flood elevation
– Develop flood forecasting and warning systems
Regional Storm Water
Modeling Program and Master
Plan for San Antonio
City of
San Antonio
San Antonio Regional Watershed Modeling System
“Bring the models
together”
Rainfall Data:
Rain gages
Nexrad
Floodplain
Management
Geospatial Data:
City, County
SARA, other
Modeling
System
Calibration Data:
Flows
Water Quality
Capital
Water quality
Improvement
planning
Planning
Integrated
Flood
Regional Water
Forecasting
Resources planning
Nexrad Map to Flood Map in
Arc 9 Model Builder
FLO
Flood map
as output
ODP
LAIN
MAP
Model for
flood flow
HMS
Nexrad rainfall map as input
Model
for flood
depth
3D Terrain Modeling
Floodplain Mapping: 3-D View
Water Supply and Droughts
http://agnews.tamu.edu/drought/pics.html
http://agnews.tamu.edu/graphics/drought98/TXrainAprJun98BG.html
Streamflow
Conditions
http://tx.waterdata.usgs.gov/nwis/rt
What can we do about droughts
and water supply issues?
• Water resource development
– Reservoirs and well fields to supply water
• Better water resources planning
– Senate Bill 1 (1997 Legislature) established 14
water planning regions in Texas
– Water Availability Modeling
– Drought forecasting (El Nino – Southern
Oscillation)
Improvements from Senate Bill 1:
Water Modeling and Planning
• Before Senate Bill 1,
water planning was
done state-wide by
TWDB
• SB1 established 14
water planning
regional groups, who
are now responsible
for planning water
supply in their area
Water Availability Modeling
(TNRCC)
Improvements from Senate Bill 1:
Water Availability Modeling
Brazos
8000 water right
Trinity
Sulphur
Colorado
locations
23 main river
basins
Rio Grande
City of Austin
Nueces
Inform every permit holder of the
degree of reliability of their withdrawal
during drought conditions (TCEQ)
CE
S
CEN
T
AT
E
W
• CRWR (UT Austin) aids in the response to
Senate Bill 1 by providing to TCEQ
watershed parameters defined from
geospatial data for each water right location
• These data are input by TCEQ contractors
to a Water Rights Assessment Package
(developed at TAMU) which determines the
% chance that the water will actually be
available at that location
• TCEQ sends the owner of the water right a
letter specifying the availability of water
FOR RESE
CH
AR
IN
CRWR Mission
for Senate Bill 1
ER
R RE SO U
R
Water Rights in the Sulphur Basin
Water right location
Stream gage location
Drainage areas delineated from
Digital Elevation Models are
used to estimate flow at water
right locations based on flow at
stream gage locations
Water Quality
Background of Clean Water Act
• 1972 Clean Water Act prohibits any
discharge of pollutants without NPDES
permit - (fishable and swimmable)
• 1987 Clean Water Act amended to require
NPDES permits for stormwater discharges
• Permits require implementation of Best
Management Practices (BMPs) to reduce
pollutant discharges to “Maximum Extent
Practicable”
Location of Impaired Waters
Austin Area Impaired Water
Segments
•
•
•
•
•
•
•
•
Bull Creek – Impaired macrobenthic community
Onion Creek – Depressed dissolved oxygen
Slaughter Creek – Impaired macrobenthic community
Waller Creek – Impaired macrobenthic community
Eanes Creek – Bacteria
Gilleland Creek – Bacteria
Taylor Slough – Bacteria
Spicewood Creek - Bacteria
What can we do about water
quality?
• Water quality enhancement structures
– Sand filters, wet ponds
– Screening inlets to storm sewers
• Total maximum daily load (TMDL)
– Comes from Clean Water Act
– Pollution load that a water body can accept and
still maintain its beneficial uses (aquatic life
support, recreation, water supply)
Requirements for Structural Best
Management Practices (BMP’s)
• City of Austin – Required since 1981,
mainly sand filters
• TCEQ – Requires removal of 80% of
sediment in stormwater for Edwards
Aquifer
• LCRA – Requires 70-75% removal of
sediment, phosphorus, and oil & grease
for Highland Lakes
TxDOT Sand Filter
Central Park Wet Pond (Austin)
Extended Detention Basin
Nueces Bay Zinc in Oyster
Tissue TMDL Project
Bay
Nueces
Imane Mrini
Center for Research in Water Resources
The University of Texas at Austin
Corpus Christi
3,000
Meters
U1
81
Zinc loads to Nueces Bay
Q = flow of water
W = load of zinc
Atmospheric deposition
Wat = 18.67 kg/d
NPS watershed loadings
Qwsh = 1.83 m3/s
Wwsh = 3.69 kg/d
Lake Corpus Christi load
QNR = 2.47 m3/s
WNR = 4.27 kg/d
Total zinc in water-Inner Harbor
Nueces Bay
70.0
60.0
Conc (µg/L)
50.0
Mean = 37µg/L
40.0
30.0
Permitted discharges
Qpd = 16.55 m3/s
Wpd = 0.71 kg/d
20.0
CP&L plant
WCP&L = 52.75 kg/d
10.0
0.0
12/1/80 8/28/83 5/24/86 2/17/89 11/14/9 8/10/94 5/6/97 1/31/00
1
Date
13430
13429
13432
13439
Inner Harbor
Average Conc. (1982-2001) = 37µg/L
Outflow
Physicochemical Reactions
sunlight
Atmospheric Deposition
Photochemical
Reactions
Flux
Inorganic Reactions
Organic/Biological
Reactions
Sediment-Water Exchange
Flux
Bioconcentration of Zinc
Total Zinc in water
( ~ 47 mg/L)
0.047 ppm
Ratio = 23,400
Ratio = 2127
Zinc in sediment
( ~ 100 mg/kg)
100 ppm
Zinc in Oyster tissue
(~ 1100 mg/kg)
1100 ppm
Ratio = 11
Academic Program at UT
• Required courses
– CE 319F Elementary Fluid Mechanics
– CE 356 Hydraulics
• Electives
– CE 358 Ocean Engineering
– CE 370K Water Chemistry
– CE 374K Hydrology
– CE 365K Hydraulic Design (Level II)
CE Faculty in Water Resources
• Randall Charbeneau (groundwater, hydraulic
design
• Ben Hodges (hydraulics, hydrodynamics)
• Lynn Katz (water chemistry)
• Spyros Kinnas (fluid mechanics, ocean
engineering)
• Daene McKinney (water resources planning)
• David Maidment (hydrology, geographic
information systems)