In mid-2022, a large dairy in Fresno County kicked off a project to drill a new 600’ well for their family-owned dairy and farming operation. All involved were confident the project would go smoothly and, once completed, would provide 1,700-2,100 gallons per minute (GPM) of water.
Unfortunately, the results were far below the expected GPM flow for an expensive project. The well barely produced 340 GPM, a fraction of the expected 1,700-2,100 GPM, and the entire project was nearly abandoned at a huge cost to everyone involved.
After unsuccessful efforts by others, Cal-West Rain was consulted as a last-ditch effort to resurrect the project and improve the well’s performance.
STEP 1 – Well Readings, Logs and Video Assessment
After the original well development company had unacceptable results, the well driller asked Cal-West Rain to review the situation and provide some recommendations to improve the underperforming well.
- The initial well readings were well below the expected flow: 340 GPM from 489 ft with 707 PPM sand and a well yield of 1.29 GPM per ft.
- Cal-West Rain videoed the well to confirm that the drilling log matched what was there, no fill-in existed, and that the well was structurally sound.
- Cal-West Rain noticed from the well video that the higher perforations in the well appeared to be dirty and were likely hindering the well’s performance.
- Based on the assessments performed, Cal-West Rain brought in one of their largest well development pumps powered by a Caterpillar C32 engine capable of running at 1000+ HP. This large development pump was to ensure more than adequate pumping power for the well surging during step 2.
STEP 2 – Intense Well Exercising and Surging
The primary goal was to exercise the well, especially the top perforations, to improve its overall pumping performance.
- Given the circumstances, Cal-West Rain treated the well with Mud-Nox® before starting the series of intense well surge/rest cycles.
- Mud-Nox® is a product from Cotey Chemical. It’s often an effective “problem solver” for challenging well development projects. Mud-Nox® is scientifically designed to help remove mud, clay, and sediment from gravel packs and producing formations of a well.
STEP 3 – Final Reading and Performance Improvement
After the process of surging/resting the well during step 2, it was time to take new readings of the well as assess its performance.
- The final well reading was significantly improved, showing 2400 GPM from 319 ft with zero/trace levels of sand and a well yield of 26.67 GPM per ft.
- Well performance before Cal-West Rain redevelopment: 340 GPM
- Well performance after Cal-West Rain redevelopment: 2400 GPM
As a side note, no water well is really completely free of sand, despite what well drillers might say, but in this case, the sand levels were so low (e.g. trace) we could not measure its presence.
Disclaimer: All wells and circumstances vary from project to project. Fortunately, in this case, the assessment and efforts by Cal-West Rain produced a very positive result for all involved, especially the end customer who needed the well for their dairy/farming operations. This situation and the results are by no means a guarantee of similar results with other well development projects performed by Cal-West Rain.
What is Mud-Nox?
Mud-Nox® is a hard-working “problem solver” for challenging well development projects. It is scientifically designed to remove mud, clay and sediment from gravel packs and producing formations. Mud-Nox increases development efficiency and well yield; reduces pumping costs; will not harm metals, rubber or plastics; and is environmentally friendly and fully biodegradable. Learn more at Cotey Chemical Corporation.
Sand Production in Wells
For basic reference, the California Groundwater Association recommends the following guidelines for allowable sand production. These guidelines are similar to those recommended by the USEPA and the NWWA. The USEPA and NWWA guidelines have been sited by several authors, including Driscoll (1986) and the Roscoe Moss Company (1990).
- 15 ppm for wells supplying water for flood-type irrigation, where the aquifer and the distribution system will not be negatively affected by 15 ppm sand (USEPA and NWWA, 1976, p. 109; Driscoll, 1986, p. 528; Roscoe Moss Co., 1990 p. 273).
- 10 ppm for wells supplying water for sprinkler irrigation systems, industrial evaporative cooling systems, and other uses where a moderate amount of sand is not harmful (USEPA and NWWA, 1976, p. 109; Driscoll, 1986,p. 527; Roscoe Moss Co., p. 273).
- 5 ppm for wells supplying water to individual homes, institutions, municipalities, and industries (USEPA and NWWA, 1976,p. 110; Driscoll, 1986, p. 527; Roscoe Moss Co. 1990, p. 273).
- 1 ppm for wells supplying water to drip irrigation and other systems which are very susceptible to plugging by sand, and for water to be used in contact with or the processing of food and beverages (USEPA and NWWA, 1976, p. 110; Driscoll, 1986, p. 527 and p. 655; Roscoe Moss Co., 1990, p. 273).
The Rossum Sand Tester should be specified to measure the sand content during the final test pumping of the well, and the limits for sand content should be met at the design pumping rate.
Other Water Well Resources
- What makes a good water well?
- What is Water Well Development?
- Mud-Nox® from Cotey Chemical Company
- Rossum Sand Tester
- CGA Guidelines for Allowable Sand Production in Wells
Cal-West Rain – Well Services and Repairs
Well development and rehabilitation require not only science but also decades of experience. While we strictly adhere to industry best practices and design specifications, our goal is to maximize the efficiency of your well. Consistent maintenance of water systems, including wells and water pumps, ensures performance and reliability. Well owners and farm managers rely on Cal-West Rain to inspect their systems to verify water levels, operating efficiency, and to identify potential problems that can lead to costly problems and downtime.
- Well development (1,000 HP+ capacity) services
- Well video inspections
- Well rehabilitation services
- Pump and pipelines inspections and repair
About Cal-West Rain
Founded in 1989, Cal-West Rain serves the irrigation and pump needs of growers and ranchers in Central California. From irrigation design to construction, pumps, automation, well services, parts and maintenance, Cal-West Rain is a full-service irrigation company with locations in Kerman, Paso Robles, Hanford and Bakersfield, California. If you need assistance, please contact the nearest Cal-West Rain branch location.