Diffuse pollution from agriculture, farming and land management has a major impact on the quality of water in our rivers, streams, lakes and ponds. Fertiliser, slurry & farmyard manure, soil and pesticides all have the potential to be washed off fields into ditches and ultimately into our rivers. Dirty water from farmyards, as well as from slurry, manure and silage stores, are also potential sources of diffuse pollution. Bacteria from livestock, such as e-coli and cryptosporidium, can cause problems for drinking water supplies for livestock and for humans. As a result, many water bodies do not meet the objectives set out under the Water Framework Directive.
By reducing diffuse pollution from agriculture, through changing farming activities, practices and land use, farmers and landowners can make important contributions to improving water quality. Many of the actions farmers can take deliver real cost savings and help to create better and more diverse wildlife habitats. Some examples of ongoing and future projects include:
The REAction WEG project works in the Rea Brook catchment. The Rea Brook is around 25 miles in length from its source: Marton Pool, near Montgomery, flowing through the Rea Valley before entering the River Severn in Shrewsbury, Shropshire.
The Middle Dee WEG project works in six of the sub-catchments on the English side of the Welsh Dee. These include the Emral Brook and Shell Brook in Shropshire, and the Worthenbury Upper Brook, Wych Brook, Aldford Brook and Henlake Brook in Cheshire.
Reaseheath staff are working with farmers and landowners to develop farm water management plans, identify opportunities for investment in measures on the farm to mitigate diffuse pollution, and establishing contractual frameworks for the delivery of ecosystem services. The work will be part of several MRes projects.
An example of one of the interventions is at Hollies Farm, Cheshire, a 100 hectare dairy farm. To prevent poaching of cattle tracks, and to protect a water body from diffuse pollution:
- A hardcore livestock track has been constructed and profiled either side of the water body
- Drainage channels have been created alongside the track to capture runoff and feed it to a series of sediment ponds
- A culvert under the track has been installed to take the water from the ponds to a constructed wetland, the final treatment stage
- Fencing of the track and ponds has been erected to prevent livestock entry.
The clean water from the constructed wetland will seep into groundwater or into the water body. The benefits are a significant reduction sediment, nutrient and biological oxygen demand of the water leaving the constructed wetland.
Turbidity, the “cloudiness” of water caused by particulate matter in water, is an indicator of water quality. Particulate matter can include sediment, especially clay and silt, fine organic and inorganic matter, soluble coloured compounds, algae, and other microscopic organisms. High turbidity can harm fish and aquatic life, increase the cost of water treatment for drinking and food processing, and reduce opportunities for recreation and tourism. Agriculture and farming can be a major source of turbidity. Sensors for turbidity monitoring, such as Sondes, are expensive and their cost limits their deployment in a river catchment.
We are working with a company to develop a low-cost turbidity monitoring system. The functionalities of the system include:
- 0 – 2000 NTU (+/- 1%)
- Real-time data logging and centralisation
- Solid-state, robust and resilient
- Multi-year battery and/or energy harvesting power options
The data the sensors collect with be available in a cloud-based system to provide support for real-time catchment-scale turbidity mapping as well as providing alerts and support for decision making. The cost of the sensor will be considerably less than that of conventional Sondes, enabling widespread deployment of the sensors within a catchment.
Natural Flood Management
Natural flood management (NFM) can offer lower cost solutions that reduce flood risk and impacts. NFM aims to reduce the maximum water volume of a flood (the peak flood flow) and/or delay the arrival of the flood peak downstream. Our work deploying and monitoring NFM solutions is helping agriculture, communities and businesses to be more resilient to climate change and extreme weather events.
We are working with farmers, landowners, and other stakeholders to implement and test NFM solutions such as:
- Creating temporary storage with retention ponds, scrapes and wetland areas that can fill up during heavy rainfall and empty slowly over a period of time
- Increasing the capacity of land and fields to “hold” water by improving soil structure, increasing organic carbon content, and removing compaction through aeration and subsoiling
- Slowing the flow of water:
- Across land (run-off) by planting trees and hedgerows, changing to contour ploughing, planting cover crops and buffer strips
- In channel by restoring meandering streams, installing leaky barriers, woody debris dams and offline storage, riparian fencing and tree planting