Morley Clean Water

Know the flow

Our first task was to identify all water courses on the farm, where they come from and go to. Sounds straightforward. However, we discovered Ordnance maps were not accurate. With some help, we drew our own farm water map using GIS software.

We monitored water flow ourselves, by taking a look and also by using time lapse cameras. We recorded large variations in flow across the day, weeks, or months.

Measure water quality

We measure water quality by testing levels of nitrogen, phosphate and turbidity. Samples are taken every month and tested with a handheld Hech 900 colorimeter. Turbidity, the measure of suspended particles, matters as nutrients (particularly phosphates) bind to the solids and are carried away with the water. We record how turbid the sample is by comparing to our simple chart.

In 18 months of testing, our samples have exceeded the EU drinking water limit for nitrate (50 mg/litre) nine times. There is no agreed limit for phosphate in drinking water. In fact, we found that often phosphate level in tap water was higher than in Morley farm ditch water.

Slow the flow of run-off on farm tracks and roads

Using our farm water map and knowledge of where we see farm water, carrying silt, flowing most, we have installed farm track cross drains and more.

For tracks, we have developed and installed a farm-made grill which track water flows into a swale (a shallow, broad, vegetated gulley) where it drops any solid particles before flowing, cleaner, off to a ditch.

Every few months we dig out the silt from the trap. The track cross drain pictured cost us about £1000 to make and install.

An alternative construction we have tried using railway sleepers cost us just £100, but it had a few limitations.

Our experience with V-notch weirs

In 2019, we installed V-notch weirs made of plywood. This tested the concept that slowing the water in a ditch, by holding back a small amount of water, allows silt to settle enabling cleaner water to flow away. The silt collected can then be periodically removed.

Our prototype V-notch weirs worked well but have begun to rot plus some water leaked around them. We have replaced them with metal V-notch weirs. They are more robust and bigger. They are sealed to the bank with clay and have not moved with the force of water. It visually noticeable that silt has collected above the weir. There have been no noticeable issues with debris collecting in the V notch.

In one location, we dug a small pool at the road edge, where often brown water flowed into the ditch, to slow the water flow. At the end of the pool, we installed a V-notch weir to hold a depth of water in the pool. The weir is adjustable as plates with different openings can be inserted to change the flow. This is an experiment. We have to be mindful that we must not cause flooding to nearby property and the highway. So far it our intervention has worked very well.