Stormwater Reuse Through Aquifer Storage & Recovery

Transcription

1 Stormwater Reuse Through Aquifer Storage & Recovery CITY OF NAPLES, FLORIDA PRESENTED BY: GREGG R. STRAKALUSE, P.E. DIRECTOR-STREETS & STORMWATER DEPT. DECEMBER 12, 2014 FLORIDA STORMWATER ASSOCIATION WINTER CONFERENCE

2 City of Naples, Florida Population: 20,537 (triples in-season with visitors) Stormwater Utility (Fee is $13.05 /ARU) $4.8 M per year Water Demand (17.33 MGD total) Irrigation: 10.4 MGD (60%) Water Supply Potable: 14.3 MGD Treated Effluent 6.72 MGD Golden Gate Main Canal Stormwater Pump Station Stormwater

3 Naples Bay Before (1950) After (2000) 3

4 Watershed 120 sq. mi. Area City 6.8% Impairments Fresh Water Nutrients (NAA) Iron Copper Bacteria

5 Background of overall program To develop up to 5 MGD of additional water sources 5 To reduce consumption of potable water from 270 gallons per capita per day (GPCD) to below 200 GPCD To conserve existing potable water supply from the Lower Tamiami Aquifer To increase supply of supplemental water for irrigation To reduce reliance on expanded water treatment facilities To meet conditions of renewed water use permit, 100% reclaimed status

6 Water Availability Critical period is March through May Assume 30% recovery Volume to meet irrigation during critical period ~ 1,000,000,000 gallons (6.24 mgd for 90 days) One ASR well delivers 1 mgd (need 6-8 wells) 6 Not all irrigation demand can be met with alternative sources

7 Water and Sewer Fund Air Blowers (Solids Monitoring) - $80,000 7 FY 2012 evaluation and design completed FY 2014 Contract awarded for Phase I for system backbone FY 2015 Phase II for suspended solids monitoring, and chlorine contact chamber and effluent waste D.O. monitoring

8 Water and Sewer Fund ASR Wells - $1,500,000 8 ASR Well 2 FY 2014 Funds allocated to install ASR Well 3 Increase storage capacity

9 Large Rig (85 +)

10 Progress to date 10 Construction began in Aug-09 Drill to 1,500 feet

11 ASR Well No. 1 Completion diagram 24-inch casing to 1,080 Storage zone 1,080 to 1,350 Plug pilot hole Schedule (cont d.) 11

12 Naples ASR Well Design STORMWATER PUMP STATION ASR WELL DURING RECHARGE ASR WELL DURING RECOVERY To Reclaimed Water Distribution System LAND SURFACE WATER TABLE AQUIFER DEPTH (feet below land surface) ,000 1,250 CONFINING BEDS CONFINED SYSTEM 1,500 MIXING ZONE INJECTED STORMWATER

13 Progress and findings to date - REGULATORY Regulatory Compliance with FDEP permit conditions Plan for entire program 13 Storage zone below USDW Separation between USDW and storage zone Compliance with District WUP Compliance with funding partnership

14 Progress and findings to date REGULATORY (cont d.) Underground Source of Drinking Water 14 An aquifer which supplies drinking water for human consumption and contains water with a total dissolved solids (TDS) concentration of less than 10,000 mg/l or less

15 Progress and findings to date UNDERGROUND CONDITIONS Geophysical logging used to collect information of sub-surface conditions 15

16 Geophysical logs 16

17 Log derived water quality 0 LOG DERIVED WQ (TDS in mg/l) 100 1,000 10, ,000 1,000, Use information related to water quality and porosity to calculate down-hole water quality Note: packer test showed TDS of 12,000 mg/l DEPTH (FEET) ~760 10,000 mg/l TDS interface estimated at 760 feet 1,000 1,100 1,200 1,300 1,400 1,500

18 Hydrogeologic column GAMMA RAY (GAPI) CALIPER X-Y ( Diameter in inches) AQUIFERS Fresh Surficial Fresh Tamiami Brackish Hawthorn Zone DEPTH (FEET) ,000 Brackish Lower Hawthorn 10,000 mg/l TDS interface 1,100 1,200 1,300 Source: City of Naples - Integrated Water Resources Plan Final Report (Tetra Tech); July 2008; ASR Well EW-1 Saline ASR zone 1,400 1,500 18

19 Transmission Main Golden Gate Canal structure 19 Intake Structure

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21 Wastewater Treatment Plant site layout Phase 2 21 ASR Well (ASR-1) Convert Exploratory Well to Monitor Well Construct ASR Well (ASR-2)

22 Schedule (cont d.) 22 ASR Well #2 & #3 ASR Well #1 location

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24 Design criteria 24 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Recovery Recharge Storage

25 Design criteria (cont d.) Average potable demand = mgd Irrigation demand (60%) = mgd 25 Available reuse = 6.72 mgd Deficit = 3.68 mgd Critical period is March through May Assume 30% recovery Volume to meet irrigation during critical period ~ 1,000,000,000 gallons (6.24 mgd for 90 days) One ASR well delivers 1 mgd (need 6-8 wells) Not all irrigation demand can be met with alternative sources

26 Transmission Main & Pump Public Works SW Station Route A Cove SW Station Route B

27 Option #1 Public Works Pump Station Station ASR Est. Capital Cost Design, Permit & Construct ASR Well Annual O&M Costs: $100,000 $ 250,000 $3,070,000

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29 Stormwater Reuse Through Aquifer Storage & Recovery QUESTIONS?