CIEEM Conference: Sustainable Management of Freshwater Resources: Bringing our Rivers back to Life

Earlier this week, on World Wetlands Day, CIEEM held an online conference looking at a range of topics focused on river recovery and bringing our rivers back to life. Penny Lewns, Vice President of CIEEM opened the morning session, with Max Wade, CIEEM President chairing the afternoon.

Anthropogenic effects are apparent in many natural habitats and are having impacts over many years. Freshwater systems are vulnerable to these impacts, and their interconnected nature means effects can be felt over a large geographical area.

Key issues

Professor Steve Ormerod from Cardiff University talked about changes to catchment characteristics such as land use and acidification ph. levels, and pollution in rivers in Wales. He mentioned how the title of this conference assumes there is a possibility to recover the previous condition of freshwater environments. Characteristics of a catchment have substantial influences on the rivers across the network, including geology, climate, soil type and rainfall pattern. People also have an impact on landscapes and catchment impacts on rivers downstream. Steve stressed how freshwater environments are losing ecological biodiversity, at roughly a rate 2-3 times higher than other systems.

How can we stop this trend and bring river environments back to life? Steve’s work in the 1980s looked at the effects of acid rain and acidity on Welsh rivers. He looked at the extent of land use change such as how planting conifers increased aluminium concentrations. Can we ever turn back this trend and bring formerly acidified rivers back to life? From monitoring areas with different land use in the Tywi catchment, some recovery has been noted with ph. levels raised and acidity intensification lowering.

Steve mentioned water pollution in urban river environments, and how cleaning up rivers (i.e. sewage control) has helped slow the loss of clean water organisms. Those species sensitive to climate change are also similar to those sensitive to poor water quality/sewage. Cleaning up water quality has helped those species sensitive to rises in water temperature, and paid a debt of what could have been a climate change impact, by tackling a water quality problem.

Dr Josh Jones, postdoc at Swansea University then presented on stream fragmentation from Europe to Wales. Josh mentioned it is important to have some inter-boundary understanding of where barriers are located. Josh presented on his research which carried out field surveys to ground-truth the locations and presence of several barriers in the dataset. His study found many new barriers which were not reported in the database.

By dividing the number of barriers by length of river, they found the highest barrier density to be in central Europe. Lower densities were found in alpine areas and Scandinavia where less development has taken place. After carrying out their estimations using the surveyed data on the ground, a correction factor was applied. This found much higher densities in areas which were already highlighted as high, with further higher densities in southern and western Europe, in Italy, Spain, Switzerland, and areas of the UK.

Under reporting of barriers was confirmed by both approaches, with mostly smaller structures (those under half a metre) being missed. Over 50% of barriers were <0.5m high in Josh’s research. A pattern was observed between UK and Europe with more developed areas showing higher density of barriers.

Nearly every catchment in the UK will have at least 1 barrier in it, therefore only 3.3% of the total river network of Great Britain is fully connected. From the database of barrier data, you could on average travel 57km without a barrier. With Josh’s fragmentation, it was closer to 4km. Removing a small density of barriers i.e. 1 or 0.5 km can have a better impact. It is better to work in weakly fragmented rivers, not heavily fragmented ones – i.e. smaller barriers, cheaper, smaller, slightly easier to enhance/remove.

Joe D’Souza, Graduate Ecologist, Arcadis presented research on another impact on fluvial systems – microplastics. Joe’s research looked at how plastics are transferred through the food web, particularly from birds feeding their young. Joe stressed how more research is needed.

Community and partnership projects

Joel Rees-Jones presented an update of the Dee LIFE River restoration Project. Restoration is a priority for Natural Resources Wales (NRW), including improving salmonid stocks in freshwater and fisheries for salmon, trout and eels. Joel mentioned the impacts of barriers to fish which struggle to pass structures. He showed an example where no fish has been seen to pass a large slab on a barrier on the River Dee.

Project objectives included removing constraints to fish migration, restoringnatural riverine processes, and improving agricultural and forestry land management practices to reduce input of nutrients. The project also looks to protect numbers of freshwater pearl mussel.

Joel talked through a few of the barriers and weirs the project is looking at removing, and stressed the importance of the location of barriers. For example the proximity of weirs to good quality habitat will prevent fish from moving upstream to habitat areas.

Lisa Barlow from Severn Rivers Trust then talked about their approach to the application of the principles of SMNR – sustainable management of natural resources. This involves a tree planting project in the Severn uplands. Lisa mentioned how trees are crucial to helping combat the climate and biodiversity crisis, and hugely contribute to restoring river catchments. The SRT approach includes adaptive management and working with uncertainty; engaging landowners; working at an appropriate scale; community collaboration to help local businesses; collecting and disseminating evidence; working towards achieving multiple benefits (such as NFM, biodiversity, health & wellbeing); and building resilience.

Water Quality

Rob Cunningham (Anglian Water) & Jonah Tosney (Norfolk Rivers Trust) presented their work on treatment wetlands: a nature-based solution for water treatment. They stressed how wetlands massively help reduce ammonia and phosphate entering out watercourses, but the WFD status shows we need to continue working and work towards good status for protected areas and species. They mentioned the importance of community engagement in implementing wetlands, and holding focus groups to see how local communities and landowners feel about establishing wetland areas.

Discussion from the conference attendees focused on the use of terminology, and whether different titles should be used for wetlands targeting sewage works treatment, and those wetlands which are naturally allowed to establish to slow nutrient runoff from land to watercourses. Discussion also focused on accumulation of phosphate and nitrates in wetlands and soils and the need for wetland harvesting to ensure efficient function. There were some thoughts around how the biomass is disposed, and how ideally phosphorous could be used on land to benefit agricultural practices.

The second speaker was Peter Powell (Welsh Dee Trust) who presented on slurry: the problem, the regulations and the solutions. Slurry is a liquid or semi liquid matter composed of livestock manure or urine mixed with water so it is flowable. This is a very concentrated matter, with likely high levels of phosphates and nitrates. Due to the nature of slurry, it easily flows, opening up a lot of pathways for how slurry can make its way into rivers. Slurry reaching watercourses can reduce oxygen levels in rivers, suffocating fish species.

Peter outlined the 3 main pathways - direct from the cow, from the farmyard, from overland flows. Cows are likely to stand in the watercourse when levels are low, providing a high concentration of slurry and manure. Fencing can be installed to stop cattle access however this can come at a high expense. Riparian buffer strips can be allowed to grow, although this too can be challenging as one grass can dominate or INNS can take over if not maintained.

Slurry from the farmyard can originate from failing farmyard infrastructure or poorly designed farmyards. Slurry can leave the farm through clean water drains or pipes which leads directly into watercourses. To stop slurry going down drains, the farmers should ensure all is collected on the farm and in slurry stores. This also benefits the farm, as the matter can be spread onto fields as fertiliser. Slurry can also be formed by nutrients washing off fields into watercourses directly. If nutrients aren’t used by the crop, they can leach out of the soil. To stop or slow this, farmers should aim for more permeable soils with better soakability.

Nature-based solutions

Tristan Hatton-Ellis presented on resilience and sustainable management of natural resources for freshwater biodiversity. He stressed the importance of thinking about river structure and processes and how we can help those to work better. Largely we need to slow water down. It can be helpful to take a catchment approach and think about the context of where you are working in the catchment. Consider flow variation and different sediment types, and how adding woody material can help enhance habitat structure and biodiversity. Tristan also mentioned the benefits of floodplains, and how river energy gets absorbed by the floodplain.

Tristan played a video of the Afon Merin, a 2020 UK River Prize Finalist and showed how the landscape had rewetted in some areas, and spawning gravels had established.

The second presenter was Alicia Leow-Dyke who gave an update on beaver activity. Alicia outlined the existing projects which have taken place involving beavers, and talked about how beavers can transform a landscape through building dams to increase the deep water and introducing woody debris to the system which are critical to invertebrate life.

Dams create hydrologic roughness to help slow the flow of water, allow land to hold more water, increasing lateral connectivity, and also hold and help filter sediments. However beavers also offer other benefits to biodiversity. They have not always inhabited wild landscapes, but have been found in urban or arable areas. This can impact upon areas especially with high levels of human activity.

Mitigation techniques can be applied in areas where beavers may have potential negative impacts. These techniques include creating small holes in the dams to slowly lower the water level. Beavers can also be translocated to other areas more suitable for their behaviour and activity. Modelling has been carried out to monitor dam suitability and capacity. The Beaver Forage Index was created to classify suitability of river reaches for dam construction, allowing areas to be highlighted which would be more suitable for beaver restoration and allowing nature based solution opportunities. Social perceptions are also important, and strong stakeholder engagement is needed.

The final presentation was from David Holland (Technical Director of Salix) who presented on Soft Engineering Approaches to River Management and Restoration. David mentioned soft engineering is usually self-repairing. Taking out hard engineering can often remove a lot of the problems.

David showed many examples including coarse wood. One example looked at using vegetation in place of rocks, which would have financial benefits as well as fewer lorries would be needed to move materials. This would take strain off of local small Welsh village roads and not cause as much local disruption.

Another example was the translocation of a large tree which was causing issues and forcing flow and erosion onto the opposite bank. The tree was removed and planted 150m upstream and is now diverting flows away from the exposed pipe works in the banks. Look how the gravel bar has been able to develop and build up!

David showed the video of River Nairn in the Scottish Highlands, a finalist of the UK 2019 River Prize.

Rivers are dynamic, so removing constraints, reconnecting to floodplains and letting the more natural processes occur is beneficial to channel recovery for morphology and ecology.

There was a lot of discussion around this topic, stressing the importance of analysing the energy of your channel for securing LWD or trees to concrete beds or banks. Soft engineering allows you to tweak the channel without significantly changing the nature of the channel which hard engineering tends to do.

Thanks to CIEEM for holding a very information conference. It ran very smoothly online and raised lots of discussion and questions from attendees.


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