Transcript Urban Water Research - University of Georgia

Urban Water Research
Todd Rasmussen
Associate Professor of Hydrology
The University of Georgia, Athens
and
Pending Director, Urban Water Research Institute
The University of California, Irvine
Atlanta, Georgia
“the fastest-spreading human
settlement in history"
Time Magazine
March 22, 1999
Ag/Poultry
Forests
Gainesville
Lake Lanier
Buford Dam
Urban Water Issues
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Stormwater Management
Nonpoint Sources of Pollution
Source Water Protection
Water Conservation
Wastewater Reuse
Wastewater Infrastructure
Roles of Science
• Data
• Data collection - monitoring and experimentation
• Data storage, and dissemination - databases
• Information
• Data interpretation - forming relationships between data
• Information storage and dissemination - information systems
• Knowledge
• Understanding relationships - predicting outcomes
• Knowledge storage and dissemination - models
• Wisdom
• Using knowledge for the public good
EPA/NSF Lake Lanier Water and Watersheds Project
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Society
Ecology
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Water quality and habitat control
community structure
Phosphorus-iron chemistry dominates
nutrient dynamics
Community beliefs and references change
Short- and long-term beliefs are different
Beliefs change in response to knowledge
Hydrology
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Water quality can be characterized using
the Rating Curve approach
Nutrient dynamics in the epilimnion and
sediments control hypolimnetic O2
Water Research Strategy
• Identify relationships at the watershed scale
– Public involvement: Defining Quality of Life
– Prioritization: Best to Worst
– Obtain information: “Soft” and “Hard”
• Develop solutions at the local scale
– Feasibility assessments: economic, legal,
engineering, ecologic, societal
– Demonstration: education and outreach
Lake Lanier Strategy
• Watershed Analyses
– Contaminant Rating Curve approach for TMDLs
– Whole-Lake Loading Rates
• Implementation Strategies
– Laboratory and Pond experiments
– Simple BMP approaches (Meta Models)
– Communicating results
Sediment Rating Curve
Suspended Solids Concentration, mg/L
10,000
1,000
100
West Fork Little River near Clermont
Chestatee River near Dahlonega
Chattahoochee River at Cornelia
Chattahoochee River at Norcross
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1
0.1
1
10
Normalized Discharge, Q / Qo
100
Phosphorus Concentration (µg/L)
10,000
Nutrient Rating Curve
1,000
100
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Point Source: Flat Creek
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10
100
Sediment Concentration (mg/L)
1,000
10,000
Take Home Message
• Total Maximum Loads can be quantified
– By using Rating Curves that correlate contaminant
concentrations with discharge
– Then establishing the concentration at mean discharge
• Preventing - reducing stormwater should be a priority
– Sediment in stormwater degrades aquatic habitats
– Stormwater contains nutrients, pathogens, etc.
Options to Reduce Nonpoint Pollution
• Stormwater Interception Strategies
– Riparian and Floodplain Protection
– Filter and Infiltration Strips
– Headwater Ponds and Wetlands
• Source Minimization
– Controls and Limits on Loading Rates
– Land Use Restrictions
Stormwater Mitigation
• Conventional stormwater disposal practices
– Stormwater channels, tunnels
– Detention basins
• Onsite stormwater disposal alternatives
• pervious pavements
• raingardens
• constructed wetlands
• wet ponds
• drywells
• infiltration strips
• mulching
• riparian buffers
• greenspaces
• contour terracing
Onsite Stormwater Mitigation
• Surface Infiltration
– Mulching, Vegetated Swales, Raingardens
• Subsurface Percolation
– Drywells, Leach Fields
• Stormwater Retention
– Constructed Wetlands
•Vegetated Swales
Drywell
Impacts of Impervious Surfaces
• Impervious areas < 10%
– Minimal impacts on aquatic systems
• Impervious areas > 25%
– Complete loss of aquatic integrity
• Treecover < 40% & Greenspace < 20%
– Increases stormwater runoff
– Degrades water quality
Implementation Strategies
• Who Pays?
– Downstream water users are willing to pay because it is
cheaper to prevent contamination than to treat the
contaminated water
– Developers are willing to pay if all parties are treated
equitably
• Who Benefits?
– Landowners are paid to reduce nonpoint source pollution
– Water users who obtain clean water
– The Environment!
What is Needed
• A watershed management authority who
– Collects fees from wastewater connections, septic
systems, water supply systems, owners of properties
with impervious surfaces
– Pays land users to reduce historical inputs
– Monitors watershed conditions to ensure that efforts are
effective
– Enforces existing laws for egregious violations
– Supports environmental education
Needed …
• Model Ordinances
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Stormwater Control
Riparian Buffers and Landscaping
Water Conservation and Grey-Water Reuse
Urban Forests and Green Space
• Other Measures
– Conservation Easements (Land Trusts)
– Transferable Development Rights (TDRs)
• More Ideas => Search for:
– “Rules for Healthy Streams”
Water Resources Programs
• Measurement and Assessment
– Water Quality and Quantity
• Effects on Aquatic Ecosystems
– Hydromodification
– Habitat Impairment
• Human Systems, Technology, and Policy
– Education and Outreach
– Demonstration Projects
– Model Ordinances
How to Assure Success
• Data Needs
– Examples of water quality treatment options
• Information Needs
– Regional differences in effectiveness
• Knowledge Needs
– Parameters or processes that are key to success
• Wisdom Needs
– Relative ability for local communities to apply
Society
Ecology
Hydrology