Diffuse pollution modelling for Catchment

ManagementUsing Scimap to model fine sediment

sources, pathways and impacts

– a presentation to NIEA, 25th April 2013

Michelle WalkerHead of GIS & Data Management

The Rivers Trust

• Background – how rivers trusts use Scimap to tackle diffuse pollution

• Running the model – assumptions and limitations

• Analysing and visualising outputs

• Where next?

• Demos: preparing data, running the model, 3D visualisation

• Rivers trusts are an incorporated charitable vehicle for catchment management that in principle anyone in the catchment community can use to:

o Raise money from charitable and other sources

o Provide necessary governance for funds

o Employ people, enter in to contracts, make commitments as if a company but free from personal liability

o DELIVER WORK ON THE GROUND

What is a rivers trust?

Rivers Trust approach to diffuse pollution

• Started around 1996 with the WRT project Tamar2000 and the ‘river-wise plan’

• Walk the river & watercourses

• Identify evidence of pollution

• Follow pathway• Identify source &

additional factors

Mitigating for diffuse pollution at the farm

scale• Buffer strips• Stock exclusion• Cover crops• Contour ploughing• Dirty water separation• Rain water collection• Moving gateways• Soil testing, fertiliser

optimisation & nutrient management

Using data & models for catchment planning

1.Assess river condition & diagnose threats

• Monitor & survey

• Characterise risk areas

2.Deliver catchment management interventions

• Create tailored plans

• Deliver interventions

3.Evaluate delivery of environmental & 2o outcomes

Justification/investigation

Delivery ofmeasures

Assessment of outcomes

Pollutant Level + Mobilisation + Connectivity = Pollution risk

SOURCE PATHWAY RECEPTOR

Pollutant Level + Mobilisation + Connectivity = Pollution risk

SOURCE PATHWAY RECEPTOR

Sediment Impacts

Background

Upstream Thinking

Upstream Thinking

Upscaling to the catchment

Source Pathway Receptor

Can we identify sources at a catchment

scale?

Can we identify unseen

pathways to the river for

interception?

Can we identify cumulative

diffuse pollution & route it back

to source areas?

++

Land use

Slope

Rainfall

SCIMAP: A diffuse pollution risk modelling framework

SCIMAP: A diffuse pollution risk modelling framework

• www.scimap.org.uk

• Free to download for non-commercial use

Using the Scimap Model

• LandcoverMap 2007 (CEH); Corine 2000; Rural Payments Agency; Local Knowledge; Remote sensing

• Ordnance Survey; Nextmap; LIDAR

• Met Office

Data requirements

++

Land use

Slope

Rainfall

Data preparation

Running the model

Model Assumptions and Limitations

• Resolution of DEM• Grips, drains,

roads, gateways, perched channels alter flow paths

• Doesn’t replace walkover

• Surface flow v ground water catchments

• Changing land use and timing

Improving the model

Incising drainage ditches in the DEM to reflect altered drainage paths

• Improving the model

Using the Scimap Model

Analysing and visualising outputs

• Need to move from catchment data & information to knowledge & wisdom

• All stakeholders need access to the information

Sharing Information for Catchment Planning

Data

Information

Knowledge

Wisdom

Understanding relationships

Understanding patterns

Understanding principles

Building a common understanding

SiltationRedox values

Scimap erosion risk and

connectivity

Inadequate buffer strips

Engage farmers & deliver

interventions

Walkover confirms arable runoff

• MyScimap – online tool funded by Durham University, The Rivers Trust and Environment Agencyo Users will be able to run model with

default data, and generate catchment on the fly

o Or upload own higher resolution DEM, landuse, etc.

o View outputs in web map or download

•Scimap user group•Video ‘how to’ guides coming soon:

www.scimap.org.uk

Where next?

Where next?

Thank you for your attentionmichelle@theriverstrust.org