California has measures in place to protect groundwater. This requires that no listed pre-emergent stay 100 feet away from wellheads, use “well-safe” herbicides, or ensure that a berm is in place around the wellhead. This is an issue that must be addressed. The Tuolumne County Road Department got cited for violation of this a few years back. So it’s serious. This is not limited to wellheads on your own property. The law is 100 feet, so if your neighbor has a wellhead within 100 feet of where you want us to spray, we need to know that too.
There are some pre-emergent herbicides that are allowed for use near unprotected wellheads:
- Oxyfluorfen Goal
- Pendimethalin Pendulum, Prowl
- Prodiamine Barricide
- Flumioxazin Chateau, Payload
These are excellent pre-emergent herbicides, but they are not sufficient to always give a high, let alone acceptable, level of control across the wide range of herbicide-resistant weed species we encounter. If these materials are used, we may need to do a followup, chargeable, spray to control any escapes.
That takes us to creating berms. The goal of a berm is to stop runoff water from entering the wellhead. On sloped ground, it’s sufficient to have the berm on the uphill side, only. On level ground, the berm needs to be completely around the wellhead. This image, from a County of Sonoma webpage, is among the best I have seen.
There is no height specifications given, but it should work under all reasonable weather conditions.
We can discuss this issue with you. Please call us if you have questions.