Virgin Valley Water District Water System Deficiencies VVWD BOARD MEETING DECEMBER 6, 2016

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Eleanor Greene
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1 Virgin Valley Water District Water System Deficiencies VVWD BOARD MEETING DECEMBER 6, 2016

2 Recap of Growth Projections 2.75% growth rate Average daily demand per Equivalent Dwelling Unit (EDU) of 410 gallons per day Peak Day Demand per EDU of 820 gallons per day

3 10 Year Growth Window Identified Hotspots within the District (Mainly Zone 1, Zone 2, & Zone 5) Allocated future demand to these hotspots Where available, specific future pipes were added to the hydraulic model Canyon Crest Blvd

4 Buildout Growth Projection Land use/zoning plans for Mesquite/Bunkerville Existing Mesquite and Bunkerville boundaries Estimated buildout population of 72,900 people Annexations/service area expansion

5 Water System Evaluation Components Water Sources (Wells) Water Treatment Facilities Water Storage Facilities Water Distribution System

6 Water Source & Treatment Facility Evaluation

7 Water Source Evaluation Criteria Criteria established by Nevada Administrative Code (NAC) 445A Annual Demand Capacity Sufficient capacity to satisfy a year s worth of demand Peak Day Demand Capacity Sufficient capacity to meet system demand during peak day usage Average Day Demand with Largest Source Out of Service Sufficient capacity to meet average day demands with largest source out of service

8 Water Source Evaluation Criteria 12,000, Water Usage Peak Day Demand 10,000,000 8,000,000 Gallons Per Day 6,000,000 4,000,000 Average Day Demand 2,000,000 Total Annual Demand 0 1/1/2015 2/1/2015 3/1/2015 4/1/2015 5/1/2015 6/1/2015 7/1/2015 8/1/2015 9/1/ /1/ /1/ /1/2015 Date

9 Annual Source Production Capacity Annual Source Production Projections Existing Groundwater Rights Existing Surface Water Rights Projected Annual Demand 12,271 AF of groundwater 11,321 AF of surface water Total 23,592 AF Paper Water vs Wet Water Annual Supply (acre-feet per year) 25,000 20,000 15,000 10,000 5, Year

10 Peak Day Well Production Capacity Well Number Estimated Production Capacity (gpm) Reliable Yield (gpm) Well No. 1A * 1, Well No Well No. 26 1, Well No. 27A * 1, Well No Well No Well No. 31 2,100 1,680 Well No Well No. 33 2,100 1,680 Total 9,750 7,800 *Anticipated to be active in 2017

11 Existing Well Sources Well No. 27A New Source #1 New Source #2 New Source #3 New Source #4 New Source #5 New Source #6 New Source #7 New Source #8 New Source #9 New Source #10 Projected PDD 30,000 25,000 Transition to surface water sources or acquire additional groundwater rights Peak Day Source Capacity (gpm) 20,000 15,000 10,000 5, gpm Existing Peak Day Supply Deficiency Year

12 Peak Day Supply Capacity For further evaluation, District was divided into different source regions.

13 Existing Peak Day Source Deficiencies Existing Conditions Source Regions A and C have surplus peak day supply capacity. Source Regions B and D are at a peak day supply deficit.

14 Future Peak Day Supply Evaluation Next 10 Years Peak day supply surplus in Region A and C. Peak day supply deficit in Region B and D Total 2,943 gpm peak day supply deficit

15 Supply Evaluation at Buildout Future Regions E and F. As anticipated, each source region is at a supply deficit at buildout (with current sources) Total deficit of 19,036 gpm at buildout

16 Average Day Demand with Well Failure Well #31 Well Failure Well #33 Well Failure

17 Source Evaluation Conclusions Annual Supply Peak Day Demand Supply Average Day Demand Supply with Largest Source Out of Service Plenty of water available, but can t get it out of the ground fast enough.

18 VVWD Arsenic Treatment Facilities VVWD operates 5 arsenic treatment plants. Combined peak capacity of 16,500 gpm, reliable peak capacity of 13,800 gpm. All treatment facilities are currently operating below peak reliable capacity. Treatment Plant Name 27 Wells Treated Well #26, Well #27A Peak Plant Capacity (gpm) Reliable Plant Capacity (gpm) Current Peak Flow (gpm) Surplus Capacity (gpm) 3,000 2,400 2, Well #28 1,800 1, Well # Well #31 4,200 3,600 2,100 1, Well #32, Well #33 6,600 6,000 2,700 3,300 Total 16,500 13,800 8,300 5,500

Condition of Source Production/Treatment Facilities With the recent failure of Well 27A, there is concern over Well #26, Well #28, and Well #29 (constructed at the same time with the same materials).

19 Condition of Source Production/Treatment Facilities With the recent failure of Well 27A, there is concern over Well #26, Well #28, and Well #29 (constructed at the same time with the same materials). Well #2 experienced a partial failure after 23 years of operation, and its current condition is questionable. Well #31, Well #32, and Well #33 were constructed using stainless steel rather than mild (carbon) steel for increased protection against corrosive groundwater. The District s arsenic treatment facilities have been in operation for 8 years, and filter media has not been replaced during that time. Chemical feed tanks may require replacement in the near future.

20 Storage Facility Evaluation

21 Storage Facility Evaluation Criteria Criteria established by Nevada Administrative Code (NAC) 445A Operating Storage Storage required to satisfy system demands during peak usage when demand exceeds source production capacity. Determined to be 25% of total peak day demand. Emergency Storage Storage to satisfy basic demands in the event of a major power outage, well contamination, or other catastrophic event. Determined to be 25% of total peak day demand. Fire Suppression Storage Storage volume required for fire suppression. Fire suppression storage was assumed to be 960,000 gallons (4,000 gallons for 4 hours).

22 Operational Storage Storage Draining Peak Hour Demand Storage Filling Peak Day Demand Hour

23 VVWD Storage Facility Schematic Lincoln #1 3 MG Lincoln #2 3 MG Scenic Tank 2 MG Decker Tank 2 MG Airport Tank 1.7 MG Flat Top Tank 2 MG Zone 6, 7 and 8 Zone 1, 3, and 4 Zone 2 Zone 5 Freeway Tank 1 MG

24 Storage Facility Evaluation Like the evaluation of the District s sources, the service area was broken into storage regions.

25 Existing Conditions Storage Evaluation District is in good shape overall in terms of storage Freeway Tank Region relies on carryover storage from higher regions. Net surplus of 5.9 Million Gallons

26 10 Year Growth Storage Evaluation New tank planned for the Pulte area. Freeway Tank Region relies on carryover storage from higher regions. Net surplus of 5.2 Million Gallons

27 Buildout Storage Evaluation Deficient regions at buildout New storage facilities for new regions of the system

28 District Storage Evaluation District is in good shape overall in terms of storage Specific system operation to utilize storage Flat Top Tank modifications Additional 6.5 MG of storage needed at buildout Ideal locations for future storage facilities Lincoln County 3 MG Tanks

29 Distribution System Evaluation

Distribution System Evaluation Criteria Criteria established by Nevada Administrative Code (NAC) 445A Minimum Operating Pressures At least

At least 30 psi during peak hour (instantaneous) demand. At least 40 psi during peak day demand.

30 Distribution System Evaluation Criteria Criteria established by Nevada Administrative Code (NAC) 445A Minimum Operating Pressures At least 20 psi during conditions of fire flow and fire demand experienced during peak day demand. At least 30 psi during peak hour (instantaneous) demand. At least 40 psi during peak day demand. Maximum Pipe Velocities To avoid excessively high pressure loss, flow velocities should be maintained to less than 8 feet per second under all flow conditions other than fire flow. Avoid Excessively High Static Pressures (>120 psi)

31 Existing Peak Day Demand Pressures Overall, peak day operating pressures look good. Some deficient areas: Bella Horizon development (31-39 psi) Hayden Estates (37-39 psi)

32 Existing Peak Hour Demand Pressures For the most part, peak hour operating pressures are adequate. One deficient area: Bella Horizon development (<30 psi)

33 Most of the system is wellprotected with adequate fire flow. Some areas do not have adequate fire flow capacity (undersized 4 and 6 lines and dead end lines). Old Mill Rd./Canal St. in Mesquite Piuate Ln./Scrub Ln. in Bunkerville Existing Fire Flow Capacity

34 Existing Static Pressure Evaluation Majority of the system is operating within the ideal range of static pressures. The lower end of Pressure Zone 2 (just north of I-15) is simulated to have static pressures greater than 150 psi.

Distribution System in 10 Years Peak Day Demand Pressure Deficiencies Bella Horizon Area Hayden Estates Turtle Mountain area of Sun City (Pulte)* Peak Hour Demand Pressure Deficiencies Bella

35 Distribution System in 10 Years Peak Day Demand Pressure Deficiencies Bella Horizon Area Hayden Estates Turtle Mountain area of Sun City (Pulte)* Peak Hour Demand Pressure Deficiencies Bella Horizon Area Hayden Estates Turtle Mountain area of Sun City (Pulte)* Northwest region of Sun City (Pulte)* Static Pressures Deficiencies Same results as the existing system (a few areas >150 psi)

Distribution System at Buildout Peak Day Demand Pressure Deficiencies Bella Horizon Area Hayden Estates Turtle Mountain area of Sun City (Pulte)* High Elevation areas in Pressure Zone 2 Peak Hour

36 Distribution System at Buildout Peak Day Demand Pressure Deficiencies Bella Horizon Area Hayden Estates Turtle Mountain area of Sun City (Pulte)* High Elevation areas in Pressure Zone 2 Peak Hour Demand Pressure Deficiencies Several areas indicated to have pressure deficiencies High head loss in transmission mains Static Pressures Deficiencies Same results as the existing system (a few areas >120 psi)

37 Distribution System Evaluation Improvements to address existing pressure deficiencies Maintain up-to-date hydraulic model to identify potential problem areas Pipe replacement program Increased transmission capacity

38 Evaluation Summary Primary focus for the District is new source development Address existing pressure deficiencies and maintain a current hydraulic model Treatment facility replacement Monitoring existing sources

39 Questions?

Section 5 - Planning Criteria. Section 5

Section 5 - Planning Criteria. Section 5 Section 5 - Planning Criteria Section 5 SECTION 5 PLANNING CRITERIA This section presents the design criteria and methodologies for analysis used to evaluate the existing distribution system and its facilities