Lake liner

Town of Fountain Hills — Town Council (2026-02-24)

View PDF Meeting page

Extracted text (via pymupdf) 2590 characters
Lake Liner Replacement Design Playbook

Fountain Park
Lake Liner Design

Better Planning 
Better Results

Lake Liner Leak Flow Chart

Leak Test

Evaporation Test Results
Once evaporation tests have indicated a lake loss greater than 110% of 
the pan evaporation, then it is recommended that planning begin for 
the liner replacement.
• To Date there has been zero indication of any lake liner outflow
• Repeat testing every 5 years

Repair Options
Inflatable Cofferdam
• Large geotextile tubes unfolded and filled with  air and water
• This enables one section at a time to be completed
• Takes longer and is more difficult to install the liner

Repair Options
Aquaphor Recharge
The lake water stored by groundwater aquifer recharge and then 
recovered for later return to the lake.
• Pretreatment Filtration
• Pretreatment Disinfection
• Microfiltration Membranes to remove suspended solids
• Dechlorination and UV Disinfection to remove undesirable by-products
• Aquifer Storage and Recovery from Well

Repair Options
Direct Reuse
• Alternative to trying to directly treat the lake water to a high level for 
aquifer recharge. 
• Provide a balance between the lower TDS AWTF water and the higher 
TDS lake water 
• Acceptable TDS concentrations for turf-grass irrigation is 200 ppm to 
500 ppm.  
• TDS of the Lake reclaimed water has been measured to be 
over 1,180 ppm.

Aquatic Wildlife Removal
• Regulatory Requirements Arizona Administrative Code R12-4
• Arizona Game and Fish Department
• Identification of lake species
• Transfer to a different lake
• Rescue aquatic life by private organizations
• Euthanizing and disposal of wildlife

Lake Sludge Disposal
Organic and inorganic solids accumulated in the lake must be removed, 
dewatered, and hauled away for disposal
• Air drying out solids not optimal

Mobile Belt Dewatering
Dewatering filtrate could be returned to the lake or 
a temporary storage area

Park Vegetation Maintenance
• Cofferdam the pumphouse cove making 200,000 gallons of water 
available to irrigate

Park Vegetation Maintenance
• Dedicated Irrigation Storage of 500,000 gallon reservoir
• 80 long x 40 wide x 21 depth

Review
• Failing to Plan is Planning to Fail
• Emergency planning is costly
• Proactive planning allows for scheduling replacement vs emergency replacement
• Water Evaporation Testing Until 110% is reached
• No difference currently, existing liner could last 50+ years, 2050s
• Design Plan: 
• Aquatic Wildlife Removal
• Removal of lake water
• Sludge Disposal
• Park Vegetation Maintenance
• Liner Replacement
• Refilling Lake

Questions