future water supply - for the ashley valley d. gerard yates central utah water conservancy district

Future Water Supply - for the Ashley Valley

D. Gerard Yates

Central Utah Water Conservancy District

Ashley Valley Water System Overview

Red Fleet Reservoir1982 operation 26,000 Acre Feet

Red Fleet Dam

Red Fleet Pump Station

1985 operational5 pumps / 2 - 8cfs (600 hp) 3 – 16cfs (1250 hp) (5/10 mgd)

Uintah Water Conservancy District

Tyzack Pipeline and Raw Water Bypass Chocolate Rock Pump Station - T2 & T3

1.5 mgd each

Ashley Valley Water Treatment Plant (CUWCD)

2 Source WatersAshley Springs / Red Fleet

Ashley Valley Water SID Treatment Plant

1 Direct Treatment Source2 Ways to Exchange

Treatment Plant Overview

Two Water Treatment Plants serve the valley Each plant has been in service for more

than 25 years – delivering high quality waterEach plant has experienced increased

demands and challenging raw water quality Each plant has experienced production

limitations during poor water quality eventsChanges in drinking water regulations

present challenges at each plant Peak production at each plant is 6-7 MDG

(CUWCD rated capacity was15 MDG – AVWSID plant rated capacity 8 MGD)

Ashley Valley Water Treatment Plant Process Improvement Project

General Plant Process Limitations

QUALITY (Lack the ability to sufficiently address increasing disinfection by-product formation)

QUANTITY (Lack the ability to treat degrading quality raw water (<5 NTU 75% of time, shut down if > 20 NTU for 3 hours or >30 NTU)

EFFICIENCY (Short “unit filter run volumes” result in higher operating costs and solids handling challenges – long hours for plant staff)

Process Improvement Evaluation

Evaluate if the existing direct filtration process is suitable from a regulatory perspective for both sources

Evaluate the reliable plant capacity achievable with direct filtration

What new processes would be required to reliably produce at the plant rated capacity?

What new processes would be required to reliably meet present and future drinking water regulations

Zeta Potential

Dissolved Air Flotation

U.V.

Pilot Plant Testing

Jar Testing

Source Water Differences ?

Site Constraints - geology

17 Acres – 20 MGD – ? Expansion to 30 MGD

Direct or Conventional ?

Filters / Under drains ?

Solids Handling ?

Finished Water Storage

Disinfection By-Products ?

Duchesne Valley – Ozone Ashley Valley – Conventional &

Blending

Utah Valley – Ozone & Conventional

Data and Process Evaluation(Decision Making)

Ashley Valley Plant Decisions

Reliably treat 20 MGD Construct a new initial hydraulic mix and

chemical feed system (lead and copper)Construct a new floc / sedimentation

process (direct to conventional)Construct new deep-bed filters with full-

rate filter to waste, a new underdrain system, and convert from declining rate filters to constant rate constant level

Ashley Valley Decisions Continued…

Construct new a new “backwash” waste water clarifier

Install a chlorine scrubber

Flocculation/Sedimentation

2 New Plate Settlers

6 Constant Level – Deep Bed Filters

New Flash Mix

New Backwash Clarifier

New Chemical Feed System

New Chlorine Scrubber

Old Plant / New Plant

15 MGD - unreliable

20 MGD - reliable

Plant Results to Date

The Ashley Valley Plant has been in operation for 9 months (with all Process Improvements Operational) and is meeting all goals and objectives.

The plant is rated for 20 MGDOne shift per day operation

Ashley Valley Total Plant Production

Both plants peak daily average is 6.5MGD AVWSID plant = 8 MGDCUWCD plant = 20 MGD2012 production both plants = 7365 acre feet10 year average = > 30 percent production

increase Present growth rate in 10 years the valley will

need an additional 2400 acre feet of treated water.

Uintah County Population Growth2000-2010 = 22.6%

Vernal City Water System 27% / 16%

Ashley Springs is a limited supply Spring highest production = poor quality

Red Fleet Reservoir (Brush Creek Spring)

The Future Supply for the Valley

2000 Acre Feet Presently Petitioned3300 Acre Feet – Presently Available

(2400 needed within 10 years)12,000 Acre Feet – Additional Jensen

Unit Water available with addition of the Burns Bench Pump Station.

There is More Than One Way to Get a Drink of Water in the Ashley Valley

Questions????