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