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.

Guadalupe River Map

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

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

T.S. Allison – June 9, 2001

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

Total Hydrograph

Pipe Flow

Overland Flow

Out

flow

Time

Pipe Flow(SWWM)

Harris Gully Watershed

Rice Blvd.

Shepherd

Greenbriar

Main St

.

Fannin

Montrose

Kirby

Harris Gully

Richmond

Westheimer

Bissonnet

Rice Blvd.

Shepherd

Greenbriar

Holcombe

Main St

.

Fannin

SW Freeway

Montrose

Kirby

Rice University

Texas Medical Center

Harris Gully

BraysBayou

Rice Blvd

Harris Gully

Digital Elevation ModelBased on 1999 Aerial Survey

DEM Used to Determine Overland Flow Connectivity and Storage

Existing Pipe Network

2-15’x15’

2-11.5’x15’

7.5’x11’

90”

60”

72”

6.5’

x10’

66”

60”

60”

72”

60”6.

5’x1

0’

66”

72”

96”

114”

54”

84”

Hermann Park

TMC

Rice

Hydraulic Calculation - Pipes

Energy Grade Line

Datum (MSL)

Flow

z1

P1

z2

P2

hL

(z + P/ + V2/2g)1 = (z + P/ + V2/2g)2 + hL

E = total energy = z + P/ + V2/2g at pts 1 and 2

Harris Gully Drains to Brays Bayou

Low Flow Box Culvert During Tropical Storm Frances

Bayou Camera - June 8-9, 2001Provided valuable data on water levels and timing

10 p.m. 12 p.m. 11:00 a.m

Texas Medical Center - Moursund Westbound6/10/01 - 6:44 AM

Rice Blvd at Entrance 16 looking west

Jeep indicating high water mark - inlet to Harris Gully

T.S. Allison - Houston, June 9, 2001

T.S. Allison vs. the 100-year(Inches of rainfall)

1-hr 3-hr 6-hr 12-hr

1976 TMC 3.8 7.5 9.8 10.4

Allison (a) 4.3 10.3 12.1 14.7

100-yr (b) 4.6 6.8 8.5 10.5

Diff (a–b) –0.3 3.5 3.6 4.2

Note: Allison dropped 8.5 inches in 2 hours