THE PROBLEM: Nutrient pollution, sludge accumulation — The lakes at Dobson Ranch are part of a man-made drainage control system, that winds through the master-planned layout. Over the years, high nutrient levels from the main inflow feed and run-off from cultivated lawns and golf course turf, resulting in increased maintenance issues and costs, as well as accumulating organic sediment concerns. This was especially the case in Lake #8, which ends in a spillway and acts as a dam, causing it to be prone to sediment accumulation. SchlixX Plus was chosen as the appropriate treatment and the results say it all!
Project Overview:
| Project Name | Dobson Ranch HOA and Golf Course Community, Lake #8 |
| Location | Mesa, Arizona |
| Lake Management Partner | Aquatic Consulting & Testing, Inc, Tempe, AZ |
| Type of water | Man-made, freshwater |
| Type and size | Drainage/decorative, 2.5 acres, 5 in in depth |
| Problem | Sludge accumulation and high phosphate levels |
| Applied Product | SchlixX Plus |
| Period and type of application | In November 2022, 1,654 lbs of SchlixX Plus was added to 2.5 acres of the total area |
| Result of the application | In May 2023, degradation of organic sludge and reduction by an average of 6 inches with the first application. Subsequently there was a water volume increase of 1.25 acre-feet and a phosphate reduction of >30% |
Background:
The lakes at Dobson Ranch, a community in Mesa, AZ, are part of a man-made drainage control system, that winds through the master-planned layout. Over the years, high nutrient levels – carried into the lakes from the main inflow feed and from run-off from cultivated lawns and golf course on the lakes’ shores – have resulted in increased maintenance issues and costs, along with concerns on how to properly address the accumulating sediment in the future. This was especially the case in Lake #8, which forms the terminus of the system and ends in a spillway which acts as a dam and is particularly prone to sediment accumulation.
Treatment:
Water and sludge samples were taken and analyzed 3 months before treatment.
SchlixX Plus was chosen as the appropriate treatment as it provides 3 key benefits:
- increases dissolved oxygen (DO) levels over a period of months
- reduces sludge accumulation through microbial digestion
- prevents the re-release of biologically available phosphate from digested sediment
Treatment was executed on November 9, 2022 and the dosage applied was 1,654 lbs of SchlixX Plus. To reduce dusting and loss of product to wind, an apparatus was used which pre-mixes the SchlixX Plus powder with water drawn from the lake and ejects it via submersed nozzles into the wake of the boat. The process took 8 hours to cover the entire 2.5 acre surface area.
Results:
Measurements and samples were taken two times in the 6 months following the treatment. Analysis of both showed significant changes in both organic sediment and phosphate levels. The sludge layer had been reduced by an average of 6 inches, with a water volume increase of 1.25 acre-feet and a >30% phosphate reduction. No negative effects on other parameters that could influence the overall ecosystem, habitability or usability of the lake water could be observed.
