1. The Woodlands - a Totally Planned Community
The community was designed as if it were fully developed with minimal impacts on water.
Strict requirements were made about land use and natural drainage concepts were used throughout.

2. Guadalupe River Map

3. 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 source of waterpower. Very high quality water source.
Major water supply and recreational river now
May become major source for San Antonio - in the near future

4. 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

5. T.S. Allison – June 9, 2001

6. Runoff in an Urban Basin
Rain falls over watershed
A portion becomes pipe flow (storm water).
The remaining portion becomes overland flow in streets and yards.
The total runoff reaches a stream and is the sum of both components
Overland Flow
Total Hydrograph
Outflow
Pipe Flow
(SWWM)
Pipe Flow
Time

7. Harris Gully Watershed
Rice Blvd
Harris Gully
Brays
Bayou

8. Digital Elevation Model
Based on 1999 Aerial Survey
DEM Used to Determine Overland
Flow Connectivity and Storage

9. Existing Pipe Network Rice TMC Hermann Park 60” 90” 72” 72” 60” 96”
66”
72”
96”
114”
54”
84”
60”
60”
60”
6.5’x10’
6.5’x10’
Rice
7.5’x11’
Hermann
Park
2-11.5’x15’
66”
2-15’x15’
TMC

10. Hydraulic Calculation - Pipes
(z + P/g + V2/2g)1 = (z + P/g + V2/2g)2 + hL
E = total energy = z + P/g + V2/2g at pts 1 and 2
Energy Grade Line hL P1
Flow P2 z1 z2
Datum (MSL)

11. Harris Gully Drains to Brays Bayou
Low Flow Box Culvert During Tropical Storm Frances

12. Bayou Camera - June 8-9, 2001 Provided valuable data on water levels and timing
10 p.m p.m. 11:00 a.m

13. Texas Medical Center - Moursund Westbound
6/10/01 - 6:44 AM

14. T.S. Allison - Houston, June 9, 2001
Rice Blvd at Entrance 16 looking west
Jeep indicating high water mark - inlet to Harris Gully

15. Note: Allison dropped 8.5 inches in 2 hours
T.S. Allison vs. the 100-year
(Inches of rainfall)
1-hr hr 6-hr hr
1976 TMC
Allison (a)
100-yr (b)
Diff (a–b) –
Note: Allison dropped 8.5 inches in 2 hours