Webinar: Monitoring infiltration and retention to support assessment of Ecosystem Services

Kathi Bauer, Natural Capital coordinator at South East Rivers Trust, gave an overview of her experience of monitoring infiltration and retention to support assessment of Ecosystem Services. This project considered water resources management and scarcity, alongside NFM, natural resources and achieving healthy ecosystems.

The project looked at measures in 2 pilot areas. PROWATER: Protecting & Restoring Raw Water Sources through Actions at the Landscape Scale, delivered a range of measures to protect and restore water resources in terms of climate change, drought and flooding. GIS and ground truthing were used, as well as an impact assessment tool. They hope to endorse a Natural Capital approach for investment in catchments.

Kathi talked about how we can demonstrate the impacts of methods, through a structured approach and indicators to consider Natural Capital. For example, we can assess what is the asset, what condition is it in, what does it supply and what is it worth?

Natural Capital = stock of assets (extent, location, condition)

Ecosystem Services = flow of benefits from Natural Capital (physical, monetary)

The Natural Capital Atlas was used to demonstrate a baseline of what condition assets are in currently. This is a good starting point to fill in local detail and compare baseline data.

The next step is looking at assets in this project, which included semi-natural grasslands, wetlands, woodland, soils, and geology. These areas were all present across the catchment and impacted by alterations or modifications in some way. The project aimed to look at where the assets were, what condition they were in, and if/how they are providing to water resources. This gives a snapshot of how our watercourses are currently functioning and whether they will be sustainable.

The specific aim of the project was the provision of water resources. This involved:

• Protect/increase recharge to chalk aquifer – reduced interception and evapotranspiration, increase filtration and retention capacity of soil
• Slow the flow – retain water in clay catchment
• Improve water quality
• Monitor how interventions impact indicators
• Validate tools 

Kathi talked us through the 3 aims involved in this project.

Aim 1 – land cover conversion looking at whether we have the right tree types in the right place. We need to convert high water-use land cover (trees) to low water-use (grass/heath) on (shallow) soils over chalk. We also need to protect biodiversity, and quantify water resource benefits. Soil moisture probes were used on these sites to monitor water content and provide the best estimate of recharge. The indicator of the impact of this intervention is drainage across the soil profile. This is important to determine which tree types, habitat types or land cover changes would provide the most benefits to water resource management.

Aim 2 – headwater wetland retention, using the example of the clay River Beult catchment. The aim was to reverse or reduce artificial draining to support natural processes. Wetland hydrological function is complex, and in the uplands, can act as source for downstream flooding. Aim to determine how we can use these areas best to make water resource management more resilient. 3 comparison sites were used, all were productive livestock farms with deciduous woodland. Level loggers were used to monitor water levels and help determine the volume of water these headwater streams contribute. Kathi stressed the importance of checking the upstream inputs or losses, to make sure you know what is coming in/could be being lost elsewhere. Make sure your level logger sites are accurate to capture the data you want – i.e. every change in level.

Aim 3 – improving soil health by introducing more diverse, deep rooting species mix on permanent pasture. Focus on agriculturally managed soils such as livestock pasture and equestrian. Understand that soil management impacts are context specific (soil type, climate, land cover) and complex. Indicators of the impacts of interventions are drainage, soil structure and infiltration rate. This project involved an interesting comparison on clay and chalk soils. Clay could be broken up to improve drainage on field adjacent to watercourse/wetland; and chalk soils could incorporate more organic matter to increase drought resilience and improve infiltration, as well as reduce nitrate inputs.

Soil samples were taken and investigated for organic matter and nitrates, allowing soil condition to be mapped. For chalk soils, the volume and duration of drainage was investigated, whilst the extent of drainage was considered for clay soils. Infiltrometers were used to determine how much water could infiltrate through the soils in a set time period. The sampling time needs to be accurate to make sure conditions are not too dry or too wet.

Lastly in regards to monitoring, Kathi mentioned costs and the importance of accurate, appropriate budget. She talked through some of the typical costs they encountered in the project. As well as monetary costs, she mentioned the importance of time, to design, investigate, research, gather advice, installation, check-ups, repairs, data downloading and analysis. Kathi mentioned the use of PRAGMO monitoring guidance from the RRC website as a great resource.

Thanks to Gerard Stewart, Kathi Bauer and everyone involved in running this webinar.