Chris Keller, P.E.
Presentation Threads
Stormwater Reclaimed Water
Dry Retention
Ponds
Rapid Infiltration
Basins Treatment Wetlands
Recharge Wetlands
Dry Retention Basins
Excavated depressions with grass or sand bottoms
Runoff percolates through soils to shallow ground water aquifer
Design runoff volume must infiltrate within a specified time frame
Basin is dry between storm events
Stormwater Reclaimed Water
Dry Retention
Ponds
Rapid Infiltration
BasinsTreatment Wetlands
Recharge Wetlands
Design for Sensitive Karst Areas
Minimum of 3’ of unconsolidated soil between limestone and basin bottom (provides reasonable assurance of adequate treatment)
Shallow as possible Maximum depth of 10 feet Fully vegetated with bahia, St.
Augustine, or Bermuda
Dry Retention Pollutant Removal
Processes
Adsorption of phosphorus and metals to soils
Physical trapping of suspended solids at soil surface
Nitrification of ammonia to nitrate in aerobic soils
Little or no biological treatment for organic pollutants or denitrification
Dry Retention Effectiveness?
FL manuals allow 100% mass removal credit for the “retained” volume…
Temporary Storage Volume
Qin Cin
Qout Water Table
Watershed Load
Pre = Post
Emerging Stormwater Issues
Effects of reclaimed water irrigation on stormwater systems (Harper 2012) 2/3 of WWTP’s produce secondary quality reclaimed
water (TN: 2-15 times stronger than runoff; TP: 8-60 times stronger)
1/3 of WWTP’s produce tertiary quality reclaimed water (similar to high density residential runoff)
Tendency by some to over-irrigate Mixing of stormwater and reclaimed water is
inevitable in some areas There is generally poor accounting of “escaped”
reclaimed water that runs off the landscape to water bodies and both reclaimed water and stormwater that reach water bodies following infiltration and transport via groundwater
Similarities between Dry Retention
Basins and RIBS
RIBS Dry Detention
Batch loading of reclaimed water
Dry (resting) period between loading cycles
Pollutants known to migrate to receiving waters
Batch loading of stormwater
Dry inter-event periods (72 hour recovery)
Migration of pollutants largely ignored
Where the water may go….
Lake Dry Ponds
RIBS
Rapid Infiltration Basins
www.waterconservii.com
Stormwater Reclaimed Water
Dry Retention
Ponds
Rapid Infiltration
BasinsTreatment Wetlands
Recharge Wetlands
Water Quality below Alachua
County RIB System
0.35 mg/L NNC for Springs
USGS Finding
“a basin loading strategy that relies on long, uninterrupted flooding offers the possibility of inducing a more anaerobic environment conducive to denitrification while maintaining reclaimed water disposal capacity”
Hydraulic Characteristics and Nutrient Transport and Transformation Beneath a Rapid Infiltration Basin, Reedy Creek Improvement District, Orange County, Florida D.M Sumner and L.A. Bradner (1996)
Is this really a problem?
Alachua
County
Where the water may go….
Dry Ponds
Spring
Can we do better than RIBS and
dry ponds, particularly in highly
sensitive areas with strong
surface water/groundwater
connections?
Treatment Wetlands are one
Tool to Consider
Stormwater Reclaimed Water
Dry Retention
Ponds
Rapid Infiltration
BasinsTreatment Wetlands
Recharge Wetlands
1967-1972 North Carolina Estuarine ponds/salt marshes 1971-1975 Massachusetts Salt marshes 1972-1977 Michigan Peatland 1973-1976 New York Constructed meadow/marsh/pond 1973-1977 Florida Cypress swamps 1974-1988 Mississippi Constructed gravel marshes 1976-1982 Florida Everglades marshes 1979-1982 California Constructed marshes 1981-1984 California Subsurface flow marshes 1990-1997 Florida Lake Apopka Flowway Project 1994-1998 California Hemet/San Jacinto Demo Wetland 1994 - 2009 Arizona Tres Rios Demonstration Project 1994-1999 Florida Everglades Nutrient Removal Project
History of Treatment Wetlands
Selected Research
Projects
1972 Bellaire, MI Natural spruce bog Municipal 1973 Mt. View, CA Constructed marsh Municipal 1975 Mandan, ND Constructed pond/marsh Oil refinery 1977 L. Buena Vista, FL Natural forested swamp Municipal 1978 Houghton Lake, MI Natural peatland Municipal 1980 Show Low, AZ Constructed pond/marsh Municipal 1983 Hilton Head, SC Natural marsh Municipal 1984 Freemont, CA Constructed marsh Stormwater 1984 Incline Village, NV Constructed evap. marsh Municipal 1984 Cannon Beach, OR Constructed/natural Municipal 1985 Poinciana, FL Natural cypress dome Municipal 1987 Myrtle Beach, SC Natural Carolina bays Municipal 1987 Orlando, FL Constructed marsh/park Municipal 1987 Fort Deposit, AL Constructed marsh Municipal
History of Treatment Wetlands
Selected Full-Scale
Projects
1991 Columbus, MS Constructed marsh Pulp & paper 1993 ENR W. Palm Beach, FL Constructed marsh Agricultural 1996 Victoria, TX Constructed marsh Industrial 1997 Tucson, AZ Constructed marsh Reuse filtrate 1999 Great Swamp EMS, SC Natural Forested Swamp Municipal 2000 Silverton, OR Constructed marsh Municipal 1999 Titusville, FL Constructed marsh Municipal 2000 Indian River County, FL Constructed marsh Municipal 2001 STA-1W, FL Constructed marsh Agricultural 2005 Green Cay, FL Constructed marsh Municipal 2009 Trinity River, TX Constructed marsh Municipal 2010 Clayton County, GA Constructed marsh River water 2011 Albany, OR Constructed marsh Municipal/Industrial
History of Treatment Wetlands
Selected Full-Scale
Projects (cont.)
An Established Technology
How Do Constructed Wetlands
Work?
Constructed wetlands mimic natural wetlands Water-loving plants Highly productive environments Naturally transform pollutants to harmless
forms Surface area proportional to performance
Cost effective treatment Solar powered No chemical inputs Minimal energy inputs
Wetland Water Quality Processes
Water
Detritus
Soils
Microbes
Roots/Rhizomes
Sedimentation and Sorption
(BOD5, TSS, N, P) Diffusion
(N, P)
Transformation and Volatilization
(C, N)
Outflow
Depth
Annual Growth Renewal Cycle
Assimilation (N, P)
Inflow
Emergent Macrophytes
Denitrification is a Key Process for Protecting Surface & Groundwater
Phosphorus Burial is the Key Process for Protecting Lakes
Orlando Wilderness Park Total Nitrogen Removal Profile
Orlando Wilderness Park Total Phosphorus Removal Profile
Wetland Ancillary Benefits
Creation of wildlife habitat
Enhanced aesthetics of “utility” infrastructure
Opportunities for passive recreational activities
Groundwater Recharge Wetland
De
pth
Be
low
S
urfa
ce
Unsaturated Surficial AquiferSaturated Surficial Aquifer
Floridan Aquifer
NO3
Spring
Storm Event Volume Dry Weather Reclaimed Application
Stormwater Reclaimed Water
Dry Retention
Ponds
Rapid Infiltration
BasinsTreatment Wetlands
Recharge Wetlands
GRU Demonstration Project
Infrastructure for parallel and/or series flow
Cell 1 is a mixed marsh community
Cell 2 is cattail dominated
Cell 3 unplanted
MW-10
3C
3N
MW-3
MW-3E
Inflow
Inflow
MW-8
MW-9
2C
MW-2E
MW-2H
MW-2
Inflow
1C
MW-1E
MW-1H
MW-1
MW-4
MW-5
MW-6
MW-7
Shallow Monitoring Well (12')
Deep Monitoring Well (40')
Horizontal Monitoring Well
Surface Water Station
CELL 1(Wetland)
CELL 2(Wetland)
CELL 3(RIB)
1W 1E
2W 2E
MW-3H
3S
Infiltration Rates
Infiltrating Wetland Surface Water
Nitrogen Concentrations
Infiltrating Wetland Shallow
Groundwater Concentrations
Deep Groundwater Quality
Deep Groundwater Quality -
Phase 2
Cell 3 Planted
Regulatory Considerations
Direct ERP permitting precedent SJRWMD – Kanapaha Middle School SRWMD – Oakmont
Permitted reclaimed/stormwater projects Golf Course Irrigation Ponds
○ Storage of reclaimed water up to the SHWL APRICOT/AFIRST – Altamonte Springs
○ Combined storage of stormwater and reclaimed water in Cranes Roost for irrigation
City of Cocoa ○ Discharge of reclaimed water to FDOT stormwater pond (TMDL
benefit to the IRL) Gainesville/GRU Sweetwater Branch Sheetflow Restoration
Project ○ Combined wetland treatment of reclaimed water and stormwater
to meet nitrogen TMDL for Alachua Sink
Potential Benefits
Dual-use of existing or planned infrastructure
Augment and protect GW and adjacent surface waters (springs, rivers, and estuaries)
Cost-effective, enhanced water quality treatment for reclaimed water and stormwater
Provide a beneficial reuse option by establishing wildlife habitat and passive public use
Questions
Top Related