Agricultural and Urban
Watersheds
Reducing Non-Point Source Pollution
Fouad H. Jaber, PhD
Assistant Professor and Extension Specialist
Biological and Agricultural Engineering
Agrilife Extension, Texas A&M University System
Urban Solutions Center, Dallas TX
Outline






The Hydrologic Cycle
What are Watersheds?
Agricultural Sources of Pollution
Agricultural Best Management Practices
Why is Urban Stormwater a Concern?
Urban Best Management Practices





Green Roofs
Rainwater Harvesting
Permeable Pavement
Rain Gardens or Bioretention Areas
Resources
Hydrologic Cycle
What is a Watershed?
50% of population
in 7 counties
81% of population
(20 counties)
Sources of Pollution
Agricultural Management Practices
1.
2.
3.
4.
5.
6.
Conservation Tillage
Crop Nutrient
Management
Pest Management
Conservation Buffers
Irrigation
Management
Erosion and Sediment
Control
Conservation Buffers
1.Grassed
waterways
2.Vegetative filter strips
3.Riparian buffers
These provide a barrier
of protection by
capturing potential
pollutants that might
otherwise move into
surface waters.
Erosion and Sediment Control
1.
2.
3.
4.
5.
6.
7.
8.
Land Grading and Slope
Protection
Topsoil
Permanent Vegetation
Permanent Mulching
Terracing
Vegetated Buffers
Streambank Stabilization
Riprap Waterways
Urban vs. Natural
Why is Stormwater a Concern?
Why is Stormwater a Concern?
Why is Stormwater a Concern?
Why is Stormwater a Concern?
Stream Degradation

Impacts due to
urbanization:

Impact to aquatic
habitat: Degradation of
habitat structure, loss
of pool-riffle structure,
reduction in base flow,
increased stream
temperature, and
decline in abundance
and biodiversity.
Fish kill at Lake Granbury.
Urban Watersheds
 Increased
stormwater peak flow
 Increased
stormwater volume
 Higher
contaminant content
 Reduced
groundwater recharge
 Flooding
 Stream
degradation
Urban Best Management Practices
BMPs that are applied at the stormwater
generation site rather than the outlet of
the conveyance system
 Purpose:




To reduce the stormwater volume
To reduce the stormwater flow rate
To reduce the pollutants in stormwater
Urban BMPs




Rain gardenbioretention areas
Porous pavements
Green roofs
Rainwater harvesting
Green Roofs
Rainwater Harvesting-Stormwater BMP
Retains water onsite
 All water applied on
high infiltration
areas (yard)
 Reduces total
volume and peak
flow
 Conserves water

What is Porous Pavement?

Porous pavement is a permeable
pavement surface with a gravel reservoir
underneath.




it temporarily stores surface runoff before
infiltrating it into the subsoil
provides water quality treatment
often appears as traditional asphalt or concrete
but is without "fine" materials
could also allow for grass growth
Types of Permeable Pavement
Porous concrete
Paver blocks
Porous asphalt
Turf Paver
Expanded shale mix
What is a Rain Garden?
A rain garden is a
beautiful landscape
feature consisting of a
planted shallow
depression that collects
rainwater runoff from
roofs, parking lots and
other impervious
surfaces.
Rain Garden
Rain Garden in Parking Lot
Benefits of Rain Gardens
In addition to its aesthetic value, rain
garden benefits include:
 Stormwater volume reduction
 Stormwater treatment
 Groundwater recharge
 Temperature buffer
How Does a Rain Garden Work?
Settling
 Chemical
reaction in soil
 Plant uptake
 Biological
degradation in
root zone

Parking Lot Design-Connected Islands
Demonstration Rain Garden
For More Information
Fouad Jaber
Extension Specialist- Water Resources
Texas AgriLife Extension
17360 Coit Road
Dallas, Texas 75252
972-952-9672
f-jaber@tamu.edu
Fact Sheets
 http://agrilifebookstore.org/
 Stormwater
Management B-6158
 Rainwater Harvesting: Raingardens
L-5482
 Rainwater Harvesting B-6153
 Graywater: B-6176; L-5480; L5504
Resources
http://texaswater.tamu.edu/storm.htm
 http://rainwaterharvesting.tamu.edu/
 http://txsmartscape.com
 http://texaset.tamu.edu/
 http://irrigation.tamu.edu/
 http://dallas.tamu.edu/
 http://aggie-horticulture.tamu.edu/
 http://urbanlandscapeguide.tamu.edu/
 http://turf.tamu.edu/
