Alamogordo Desalination Project

Transcription

1 Alamogordo Desalination Project 2015 Multi State Salinity Conference Robert Fowlie, PE, BCEE February 19, 2015

2 Alamogordo Regional Water Supply Project

3 Existing Water Sources Surface Water City has 5400 AFY of surface water rights. Approximately 70 percent of the City s water supply is provided by surface water sources. Surface water comes from the Sacramento Mountains east of the City and from Bonito Lake 90 miles northeast of the City. Bonito Lake supplies approximately 25 percent of City s water supply. Bonito Lake supply lost in 2012 due to Little Bear Fire.

4 Existing Water Sources Ground Water City uses ground water to supplement surface water supply AFY of ground water rights. Ground water supplied by 9 wells. Groundwater high in TDS ( mg/l) blended with surface water. Groundwater supply affected by drought (water levels dropping, production reduced).

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6 Bonito Lake

7 Need for Project Water Supply Need for future water supply based on concept of Firm Water Supply. Firm Water Supply the reliable withdrawal rate of acceptable quality water that can be supplied by available flows and/or storage releases from reservoirs and/or groundwater reserves throughout a critical drought period (AWWA M50). Method uses past data to estimate what can be expected in the future. Same methodology used to estimate firm supply of groundwater.

8 Need for Project Demand and Supply Requirements Projected Water Demand and Water Supply Requirements 2015 to 2050 Year Total Demand (AFY) Ground Water Supply 2 (AFY) Surface Water Supply (AFY) Additional ARSWP Supply Required (AFY) Additional ARSWP Supply Required (MGD) ,185 3,909 2, , ,626 3,909 2, , ,095 3,909 2, , ,594 3,909 2, ,122 3,909 2,525 2, ,685 3,909 2,525 3, ,279 3,909 2,525 3, ,914 3,909 2,525 4, Reference: Draft 40-Year Water Plan, Livingston Associates and John Shomaker and Associates Existing ground water sources 3- Assumes Bonito Lake is out of service until Assumes Bonito Lake is in service

9 Alamogordo Regional Water Supply Project Develop 4000 AFY of brackish groundwater from Tularosa Basin as a new source of water for the City of Alamogordo. Project to completed in phases - First phase consists of development of 1 MGD treatment plant. Future expansions to ultimate capacity of 4 MGD.

10 City of Alamogordo Desalination Treatment Plant

11 Concentrate Disposal Interim Plant will use evaporation ponds for concentrate disposal 13 acres of ponds provides storage for 4 months of plant operation (30.25 MG or 93 AF) Ponds are double lined (2-60 mil HDPE liners separated by geonet) Future expansions in production capacity will require injection well for concentrate disposal

12 Overall Site Plan

13 Regulatory Requirements Groundwater Discharge Permit required for concentrate disposal Oversight from NMED Solid Waste Bureau due to buried solid waste on plant site New Mexico Office of State Engineer (NMOSE) permit for withdrawals from Snake Tank Well Field

14 Groundwater Discharge Permit Lead agency is New Mexico Environment Department Ground Water Quality Bureau (GWQB) Permit application requires following information: Volume of discharge Quality of discharge Depth to groundwater table (most shallow) Quality of existing groundwater (TDS) Public Notice Permit requires preparation of Operational, Monitoring, Contingency, and Closure plans

15 Groundwater Discharge Permit Monitoring Construct 3 monitoring wells (one upstream of ponds, two downstream) Sample quarterly (or more frequently depending on permit) Leak detection weekly (inspection by operator) Operations solids removed from ponds every 5 years Ponds are filled simultaneously

16 Groundwater Discharge Permit Evap Ponds Contingency Plan (Discharge piping or liner failure) Isolate piping and repair Drain pond and repair liner Notify NMED! Closure Plan Cap piping, remove solids and liner Test soils under liner Fill in pond and regrade site City will abandon 2 ponds in future; use one for emergencies if injection well fails

17 Regulatory Requirements Solid Waste Bureau Plant site is located adjacent to former Alamogordo Landfill City conducted Focused Environmental Investigation during preliminary design Buried solid waste encountered throughout plant site and in area of evaporation ponds - Buried solid waste varied in depth below grade and in thickness Landfill gas was not detected in any of the LFG wells

18 Plant Site in Relation to Alamogordo Landfill

19 Focused Environmental Site Investigation

20 Regulatory Requirements Solid Waste Bureau Solid Waste Bureau wanted all solid waste removed; not cost effective Developed engineered solution acceptable to NMED Settlement Analysis of pond liner Landfill gas venting system under liner Landfill gas venting system under treatment plant Deep foundation system LFG monitors inside treatment plant building

21 Regulatory Requirements Injection Well Concentrate disposal for future expansion will be an injection well Permits for injection wells are not common in New Mexico Regulations require permit from GWQB coordination with Oil Conservation Division Class I Injection well will be required inject fluids below formation containing TDS less than 10,000 mg/l

22 Regulatory Requirements Injection Well City conducted Hydrogeologic Assessment for injection wells Suitable formations for injection at the desalination plant site ( feet bgs) Test well is required to determine thickness and characteristics of formation Detailed hydraulic analysis (groundwater flow modeling) will also be required City to pursue this option once Interim Plant is completed and producing treated water

23 Regulatory Requirements NMOSE Permit NMOSE issued permit for groundwater withdrawals from Snake Tank Well Field City is limited to 4000 AFY - can withdraw 5000 AFY in a calendar year sum of annual diversions cannot not exceed 20,000 AFY over a five year period. Permit issued based on water demand of 165 gpcd Install monitoring wells in vicinity of Snake Tank Well Field monitoring must begin before production wells are completed.

24 Project Status 30% Design is complete Ground Water Discharge Permit application has been submitted waiting for comments from NMED Construction scheduled for