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Las Delicias , El Salvador Water Supply Project. Implementation Proposal Phase I Trip Dates: May 2012 Presented to TAC: March 7, 2012. Presentation Outline. Overview of Las Delicias Community Current Water Supply System and Challenges Proposed Improvement to Water System
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Las Delicias, El SalvadorWater Supply Project Implementation Proposal Phase I Trip Dates: May 2012 Presented to TAC: March 7, 2012
Presentation Outline • Overview of Las Delicias Community • Current Water Supply System and Challenges • Proposed Improvement to Water System • Phase I (May 2012) • New Water Tank at Intermediate Elevation • New Supply pipeline and distribution pipeline • Phase II (Fall 2012) • New pump • Improvements to distribution system • Logistics and Implementation
Las Delicias, El Salvador Las Delicias
Las Delicias, El Salvador • Project History • Project FIAT and FIMRC have been active in Las Delicias for > 5 years • Initial Contact with Project FIAT • January 2009 • Application to EWB-USA • March2009 • Project Approved • May 2009 • Preliminary Assessment Visit • July 2009 • First Assessment Trip • July 2010 • Second Assessment Trip • November 2011 • Community Facts • ~600 homes, 2700 residents • 15 miles NW of San Salvador • On Western Slopes of Volcan San Salvador • Homes Spread Out, but Las Delicias is Bordered by Several Similar Communities • Water Storage & Piping System installed 20 years ago With Water Delivery by Truck • Well and Pump Installed < 5 years ago • Residents are Poor (<$10/week income) • Community Well-Organized through Adesco and NGOs (FIAT & FIMRC) • Able to spend about $5 per household on water each month
Map of Las Delicias WaterSystem DOWNHILL
Current Las Delicias Water Supply & Storage System • Pump Runs 6 Hours a day 4 days/week ~ 26 hr/wk. • Pump flow rate: 175-200 GPM.
Map of current Las Delicias Water System from ADESCO with approx house locations indicated 260 Homes Served by Tanque 3 291 Homes Served by Tanque 1 33 Homes Served by Tanque 2 DOWNHILL
Challenges to Las Delicias Water Supply System • High electric cost • Typical ADESCO revenue from water fee ~$2300/mo • Typical monthly cost for water system ~$2000/mo (mostly electicity ~$1500/mo) • Pumps run about 26 hr/wk • Not taking advantage of nightime off-peak rates • Power factor on pumps leads to monthly fine • Inequitable water distribution • Some homes report receiving water <1x/week and low flowrates • “Valvulero” controls distribution via valves to zones (“Tramo”) throughout community • Large number of new homes at low elevation • Culture of scarcity where residents hoard water when it is flowing • Water Quality: • Effectiveness of in-line chlorination is not clear
Monthly Income for Las Delicias ADESCO Electric Bill Water System Expenses
Alternatives Analysis Summary • Drilling another well ($3500 for hydrogeological study) • Solar power for pump (eliminated due to cost >$50K) • Additional tank locations (three considered – current location on public land and co-located with current tank) • VFD (variable frequency drive – does not add much efficiency)
Proposed Updates to Las Delicias Water System • Objectives • Utilize existing and new tank at intermediate elevation to supply water to lower half of Las Delicias • With new pump and supply line reduced electricity costs • Improved distribution system more equitable water supply to all homes (especially at lower elevations) • Phase I (May 2012) • New Water Tank at Intermediate Elevation • New Supply pipeline and distribution pipeline • Phase II (Fall 2012) • New pump • Improvements to distribution system • Improving power factor for pump via capacitors? • Enabling pumping during nighttime to take advantage of lower rates
Proposed Water Distribution System 280 Homes Served by New Tank 117 Homes Served by Tanque 3 33 Homes Served by Tanque 2 154 Homes Served by Tanque 1 DOWNHILL
Summary of potential changes in water distribution system CURRENT SYSTEM PROPOSED MODIFICATION Storage Tanque 1: 35,000 gal Tanque 2: 11,000 gal Tanque 3: 25,000 gal New Tank: 28,600 gal Current 65 HP Pump supplies water to Tanques 1 & 3 at 175 gpm New pump supplies water to new tank at 175 gpm with much lower head Homes serviced by Tanques 154 33 117 New: 280 • Storage • Tanque 1: 35,000 gal • Tanque 2: 11,000 gal • Tanque 3: 25,000 gal • Pump supplies water to Tanques 1 & 3 at 175 gpm, ~3 days per week • Spring supplies water to Tanque 2 (and other tanques) • Homes serviced by Tanques • 291 • 33 • 260 New tank reduces demand of water from Tanques 1&2 (which require high head) by roughly 50%
Map of Current Water System (section relevant for EWB-MAP modifications)RED lines – supply lines to tank (uphill by pump)BLUE lines – distributions lines by gravity DOWNHILL Exisiting 11,000 gallon tank
Proposed update to Water System (section relevant for EWB-MAP modifications)RED lines – supply lines to tank (uphill by pump)BLUE lines – distributions lines by gravity A F NEW DISTRIBUTION LINE 2a NEW SUPPLY LINE 1 D NEW DISTRIBUTION LINE 2b E DOWNHILL NEW DISTRIBUTION LINE 2c B NEW TANK C
Tank Design response to J. Knight concerns • Concrete block vs poured concrete. Block recommended by Daniel Rivera. • Assumed strength of concrete (2000-3000 psi acceptable) • Tank seal at base of wall
Design of Additional Pipelines for- supplying water to tank- distributing water Proposed update to Water System (section relevant for EWB-MAP modifications)RED lines – supply lines to tank (uphill by pump)BLUE lines – distributions lines by gravity A F NEW DISTRIBUTION LINE 2a NEW SUPPLY LINE 1 D NEW DISTRIBUTION LINE 2b E DOWNHILL NEW DISTRIBUTION LINE 2c B NEW TANK C
NEW TANK Supply Pipe 1 Pipe Profile RoadCrossing RoadCrossing C 655 m B 651 m 105 m Elevation: 640 m D 643 m 640 m 240 m A 638 m Tee connect to 6” pipe Gate Valve 45° Elbow 90° Elbow with anchor 90° Elbow Pipe Exit Tee with Manual Air release valve Tee with Manual drain valve Gate Valve 90° Elbow PIPE FITTINGS
Estimate of head losses in supply pipe 1 (smooth PVC) 4” PVC sufficient to keep major and minor losses to <10% of the elevation change
Supply Pipe 1 Trenching • Based on recommendations from EWB Water Resource Guidelines and advice from Tony Sauder: • 70 cm trench depth (45 cm depth acceptable except in road crossing) with pipe buried below 50 cm • 10 cm bedding (2-12 mm soil) if stones/rocks present in trench • Back-fill with soil that is free of lumps, from stones (>3 cm), and from organic matter • PVC pipe joined in trench and cure for >10 hr prior to pressurizing. Keep joints exposed to check for leaks. Expansion joints not necessary • For road crossing, may bury PVC pipe inside steel or concrete pipe (ID > diameter of PVC joints); final decision to be made in the field after evaluating potential for erosion 50 cm 70 cm trench depth 10 cm 10 cm bedding
Valve Boxes • Design options • Obtain pre-cast valve boxes with lockable lids locally • Build from bricks and mortar with metal lids • Specifications • 4” Pipe centered about 55 cm below ground level • Box should extend 10 cm above ground level • Internal dimensions roughly 45cmx45cm • Place support under valve Photos of current valve boxes installed in Las Delicias
Thrust Anchors for Elbows &Tees From Russ Turner, Tetratech
Summary of Finances for Implementation • Include contribution from community to construction, etc.
Schedule for Implementation • BRIAN
Material Procurement • Emphasize connections through Project FIAT
Metrics • Increase water supply by ~20% • Increase in % of homes receiving sufficient water (at least 2x per week)