Catchment and river applied research (CaRAR) River at sunset 
CaRAR provides applied research and expertise for river and catchment management across the UK and overseas. As part of the School of Geography, Earth and Environmental Sciences, the CaRAR team draws upon a broad range of expertise in the fields of hydrology and fluvial geomorphology, ecology and environmental chemistry to deliver a wide range of environmental diagnostic services. We work closely with catchment stakeholders to provide tailored, high quality research outputs enabling targeted management of environmental problems in river systems. 
The CaRAR team specialises in: 
  • Surface water quality assessment 
  • Contaminant bioavailability 
  • Sediment – contaminant mobility 
  • Sediment source apportionment and system connectivity
  • Hillslope soil erosion and deposition
  • Catchment sediment budgets
  • Siltation rates
Infiltration measurements. CaRAR 2 men looing at soil
CaRAR man working next to a river
CaRAR - man working in the woods next to a river with technical equipment 

Consultancy team



Full surface water quality assessments in line with Water Framework Directive & Common Standards Monitoring guidance

CaRAR has extensive experience in delivering detailed water quality assessment of surface waters throughout the UK, working alongside statutory bodies, environmental charities and land user groups. Our team will design and implement detailed catchment sampling strategies, supported by UKAS accredited sample analysis, and provide tailored, high quality reporting of results.

High temporal resolution monitoring of water quality parameters

Deployment of instrumentation for continuous monitoring of river flow and key water quality parameters (e.g. turbidity; conductivity; dissolved oxygen; temperature, pH; ammonium). Data can be used to assess contaminant-flow relationships and, if combined with automatic water sampling, determine suspended sediment-contaminant loads and hysteresis.

Sediment source apportionment

Sediment source fingerprinting approaches are used to determine key land cover and tributary sources within river systems, supporting targeted management practice. CaRAR undertakes source and receptor sampling and provides high quality analyses of chemical composition in our IS09001:2015 certified radioisotope facility, prior to determining key sources using a novel Bayesian mixing model approach.

Sediment residence time investigation

As well as determining key sources of fine sediment in river channels, estimations of sediment residence time are important for assessment of channel condition and impact upon biota. CaRAR has extensive knowledge of radioisotope tracing techniques to provide robust estimates of sediment residence time in river systems.

Assessing catchment contaminant spatial distributions

Combining sediment risk mapping and channel bed sediment sampling to determine nutrient (phosphorus) and metal concentrations in stored material. Sampling is supported by UKAS accredited wavelength-dispersive X-ray fluorescence (XRF) analysis and in situ determination of elemental concentrations using field-portable XRF instrumentation.

Assessing phosphorus mobility in stored sediment

Exploring the role of sediment storage zones as nutrient sources through the use of diffusive gradient in thin films (DGT) technology to determine labile, potentially bioavailable phosphorus fractions in stored channel sediments.

Siltation rates using sediment geochronology tools

CaRAR has a strong track record in the use of radionuclide dating techniques to determine sediment accumulation rates in lakes, reservoirs, channel floodplains and tidal wetlands, underpinned by analytical expertise in the ISO9001:2015-certified Consolidated Radioisotope Facility (CoRiF).

Catchment sediment budget investigation

The CaRAR team provides detailed catchment sediment budgets by combining assessments of hillslope soil and sediment redistribution, sediment source apportionment, sediment storage and suspended sediment flux.

Project examples

Identifying fine sediment inputs to key freshwater pearl mussel sites-Scotland

Client: APEM Ltd for Scottish Natural Heritage. CaRAR was responsible for assisting with the sampling strategy design and modelling, interpretation and reporting of the sediment tracing component of a wider study for Scottish National Heritage.

Assessing the suitability of potential freshwater pearl mussel translocation sites in the River Clun

Client: Natural England. CaRAR developed and implemented a robust sampling strategy utilising continuous monitoring instrumentation, water spot sampling and automatic water sampling to assess key water quality parameters against Favourable Condition Targets (FCTs), providing detailed reports tailored to the client’s requirements.

Temporal and spatial patterns of phosphorus concentration across the ditch system of West Sedgemoor SSSI

.Client: Natural England. CaRAR undertook an extensive monitoring programme across a water year to assess phosphorus dynamics in a highly complex ditch system, liaising closely with Natural England, the Environment Agency, the RSPB and Internal Drainage Board. The CaRAR report informed future management decisions and underpinned further nutrient flux research at the site.

Assessing the input of road-derived contaminants to the River Teign

Client: Westcountry Rivers Trust. CaRAR implemented a monitoring campaign using both routine and storm water sampling, alongside continuous monitoring, to determine contaminant pathways and assess surface water quality in line with Water Framework Directive Environmental Quality Standards.

Fine sediment and phosphorus contamination in southwest rivers (Taw and Teign)

Client: Westcountry Rivers Trust. Sampling was undertaken along channel transects to quantify fine sediment storage and total phosphorus concentrations, identifying sediment-contaminant hotspots. The information was used to inform targeted management practice relating to potential point and diffuse sources of nutrients to the river systems.

Sources and quality of fine sediment in degraded freshwater pearl mussel habitats (Clun and Mease)

Client: Natural England with APEM Ltd. CaRAR undertook an extensive monitoring project across a series of linked contracts to assess key sediment sources using novel fingerprinting approaches, and to determine sediment-contaminant concentrations throughout the catchment.