Rivers and Wetlands
Rivers and wetlands are a valuable environmental resource, which contribute to the diversity of landscape and habitat in the county. They are also an important economic resource supporting tourism based on walking, canoeing, angling or shooting. Many of the county's major rivers are used for domestic and industrial water supply. The quality of their water is affected by the management of both the watercourses themselves and their wider catchments.
The management of rivers and wetlands involves many organisations and private individuals. The Environment Agency is the principle regulatory body, and has prepared Local Environment Agency Plans (LEAPS) for the Tyne, Wear and Tees catchment areas which deal with many of the issues set out below. The European Water Framework Directive is a new piece of legislation which promotes a new approach to water management through river basin planning. River Basin Management Plans will be produced for each River Basin District by 2009. The county falls within the Northumbria River Basin District.
Issues and Objectives
Deep mining for coal on the Durham coalfield has ceased and there is no longer a need to pump groundwater to protect underground workings. Cessation of the pumping currently carried out by the Coal Authority could lead to severe pollution of rivers and streams with mine-water which is both acidic and contains rusty deposits of iron hydroxide. The situation is monitored by the Environment Agency. There are existing discharges from a number of old spoil heaps on the coalfield, and from metalliferous mines in the dales, which affect water quality. A number of these have recently been improved through the use of reed-beds.
- To protect the rivers and streams of the coalfield from pollution by mine-water.
- To encourage the improvement of existing discharges through the use of natural solutions like reedbeds.
Loss of Bank-side Vegetation
Natural bank-side vegetation has been lost in many places due to urbanisation, river engineering, grazing by livestock or the cultivation of land up to bank edges. Loss of bank-side vegetation can damage the structure of rivers and streams leading to increased erosion, widening and shallowing of channels, siltation of spawning beds and a general decline in habitat quality and connectivity.
- To promote the restoration of natural bank-side vegetation, and particularly wet woodland, along the county's rivers and streams.
Spread of Invasive Species
A number of invasive alien species are becoming increasingly widespread, principally Himalayan Balsam, Japanese Knotweed, and Giant Hogweed. These species can displace native bank-side vegetation.
- To encourage the control of invasive species and the improvement of riverbank habitat to make it less susceptible to colonisation.
Loss of Field Ponds
Field ponds, both natural and artificial, are important features of the landscape in many parts of the county but have declined in number and quality in recent decades. As their role in watering livestock has diminished, ponds have been drained, in-filled or become choked with vegetation and silt. This has lead to fragmentation of the habitat and increased genetic isolation of less mobile aquatic or amphibious species. We need to increase our understanding of the distribution of ponds in the county and its implications for wetland species.
- To encourage the restoration and creation of field ponds.
- To promote a 'whole landscape' approach to the management and creation of ponds.
The water in some of the county's rivers and streams is of poor quality, often as a result of discharges from sewerage treatment works or combined sewerage overflows. This affects both the habitat value of the watercourse and its recreational use. Often those rivers or streams with the poorest water quality are in heavily populated areas and have potentially high levels of recreational use.
Parts of the county are identified as Nitrate Vulnerable Zones - areas where nitrate from agricultural land is causing pollution of the water environment. In these zones Action Programmes of compulsory measures apply including requirements for farmers to limit their applications of livestock manures.
- To support the continued improvement of water quality in the county's rivers and streams.
- To promote the use of natural systems like reed-beds in conditioning water.
- To promote the adoption of uncultivated or tree-planted margins to ditches and watercourses and particularly in Nitrate Vulnerable Zones.
Drainage of Upland Bogs and Mires
Drainage of moorland bogs by gripping was carried out extensively in the 1960s and 1970s. Gripping leads to the rapid run-off of rain and snow melt, increasing the risk of flash flooding, and the drying out of peat margins. Over deepening of grips has lead to areas of severe erosion on some moors and increased sediment load and siltation in watercourses downstream. This has adverse impacts on both fisheries and water abstraction. The decomposition of moorland peats is also a major contributor of atmospheric CO2 which contributes to global warming.
- To support and encourage the restoration of natural hydrological conditions in the County's peatlands.
Drainage of Wetlands and Wet Grasslands
Wet grasslands across the county have been in progressive declined for decades due to improvements in field drainage and larger scale land drainage and flood alleviation schemes. Wet or seasonally flooded grasslands are a particularly important feature of the uplands and upland fringes, river floodplains, and the poorly drained carr landscapes of the lowlands.
- To encourage the restoration of natural hydrological conditions to wetland systems and particularly river floodplains, lowland mires and lowland carrs.
- To encourage the conservation and restoration of wet grasslands
New development in the form of housing, industry, roads and mineral sites can have substantial, if largely hidden, impacts on the water environment. Development on floodplains can reduce flood storage or require flood protection. Impermeable surfaces such as car parks and roads create increased rates of run-off and a reduction in water quality.
- To promote 'sustainable urban drainage'.
- To protect floodplains from inappropriate development.
Engineering of Watercourses and Ditches
The majority of rivers and streams in the county are relatively natural in their structure, but many have been modified by flood berms, by channel straightening or profiling, or by structures such as weirs and culverts.
- To promote the restoration of natural 'dynamic' conditions to watercourses and floodplains where possible.
- To promote the adoption of more 'natural' techniques in river engineering works
- To promote good practice in managing ditches and engineered watercourses to maximise biodiversity and enhance landscape character.
Reservoirs and Treatment Works
The county contains a number of reservoirs, most notably in the upland dales and dale-heads, developed in the nineteenth and twentieth centuries. Some of their features - and particularly engineered structures and bare drawdown zones - can look alien or visually intrusive in the upland landscape. Across the county sewerage treatment works are found close to many settlements. These are generally small in scale but can be visually intrusive in rural locations.
- To encourage the enhancement of the setting of reservoirs and particularly through the planting of new native woodlands where appropriate.
- To improve the appearance of treatment works in rural locations through design detailing, tree and woodland planting.