Devon and Cornwall Soils Alliance - Knowl Water by Westcountry Rivers Trust

Knowl Water Devon and Cornwall Soils Alliance

This document was produced by the Westcountry Rivers Trust for the Devon and Cornwall Soils Alliance (DCSA) project, funded through the Environment Agency Water Environment Grant.

Contents This pack contains maps of the Knowl Water catchment. This catchment is one of the 7 waterbody catchments being targeted in the feasibility study stage of the Devon and Cornwall Soils Alliance (DCSA) project. There are also 2 Special Area of Conservation catchments being focused on in another part of the project. Each page focuses on a different theme, and uses maps, tables and graphs to provided spatial information about the catchment. Rivers, roads, and settlements are also included in the maps. A full list of data sources can be found on page 22.

Overview

Land Cover

Soils Soil Type

Soil Composition

Soil Hydrology

Soil pH

Geology

Crops

Habitats

CEH Natural Capital Maps Topsoil Carbon

Topsoil Nitrogen

Topsoil Phosphorus

Topsoil Invertebrates

Topsoil Bacteria

Land Ownership

River Condition

Flood Risk

Hydrological Connectivity

Slope

Data Sources

Overview The 9 DCSA catchments are spread across Devon and Cornwall. The Knowl Water catchment (highlighted in red) is located towards the north coast of Devon, to the west of Exmoor.

The area mapped in this report is the Knowl Water Waterbody Catchment, as delineated by the Environment Agency for the Water Framework Directive (WFD). It is part of the Taw and North Devon Streams Operational Catchment, and feeds into the Taw-Torridge Estuary. The waterbody has one main stem of river which is assessed together under WFD, which is fed by several smaller tributaries. The lower end of the catchment reaches the outskirts of Braunton and Wrafton, and there are several other small villages within the catchment.

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Land Cover Land Cover Map 2015 (LCM2015) is derived from satellite images and digital cartography and provides land cover information for the entire UK. Land cover is based on UK Biodiversity Action Plan broad habitats classes.

Urban/Suburban, 5% Broadleaved Woodland, 9%

Arable and Horticulture, 33%

Improved Grassland, 53%

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Soil Area Type NATMAP Vector is the principle set of soil data held at Cranfield University. It is a 1:250,000 scale map of England and Wales, showing the locations of 297 distinct soil associations. Within each of the soil associations are multiple soil series.

MANOD, 22%

DENBIGH 1, 78%

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Soil Area Composition The map below shows the percentage of sand, silt, and clay in each soil area. Sand is subdivided into fine, medium, and coarse percentages. The table gives additional descriptive information on each soil area.

Soil Series

Series Definition

Soil Subgroups Soil Layer

Dominant Soils

Associated Soils

MANOD - loam over shale

medium loamy material over lithoskeletal mudstone and sandstone or slate

typical brown podzolic soils

mineral topsoil

Well drained fine loamy or fine silty soils over rock.

Shallow soils in places.

typical brown earths

mineral topsoil

Well drained reddish coarse and fine loamy soils over gravel, locally deep.

Some similar soils affected by groundwater.

reddish light loamy NEWNHAM - loam material over nonover gravel calcareous gravel

DENBIGH 1 - loam over shale

medium loamy material over lithoskeletal mudstone and sandstone or slate

typical brown earths

mineral topsoil

Well drained fine loamy and fine silty soils over rock.

Some similar soils with slowly permeable subsoils and slight seasonal waterlogging. Shallow soils and some bare rock locally.

WALLASEA 1 seasonally wet deep clay

clayey marine alluvium

pelo-alluvial gley soils

mineral topsoil

Deep stoneless noncalcareous and calcareous clayey soils.

Soils locally have humose or peaty surface horizons.

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Soil Area Hydrology The map and table below give information on the hydrology of the soil areas.

Soil type Hydrology 4

Free draining permeable soils on hard but fissured rocks with high permeability but low to moderate storage capacity.

Free draining permeable soils in unconsolidated sands or gravels with relatively high permeability and high storage capacity.

Free draining permeable soils in unconsolidated loams or clays with groundwater at less than 2m from the surface.

Soils seasonally waterlogged by fluctuating groundwater and with relatively slow lateral saturated conductivity.

Relatively free draining soils with a large storage capacity over hard impermeable rocks with no storage capacity.

Slowly permeable soils with slight seasonal waterlogging and moderate storage capacity over slowly permeable substrates with negligible storage.

Relatively free draining soils with low storage capacity over hard impermeable rocks with no storage capacity.

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Soil Area pH The map below shows NATMAP Vector information on the average pH level of each soil area.

6, 100%

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Geology The map below shows British Geological Society 1:50 000 scale bedrock geology.

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Crops The Crop Map of England (CROME) contains approximately 32 million hexagonal cells classifying England into over 20 main crop types, grassland, and non-agricultural land covers, such as woodland, waterbodies, fallow land and other non-agricultural land covers. The classification was created automatically using satellite images in late January 2018 â&#x20AC;&#x201C; September 2018.

Winter Barley, 2% Maize, 2% Winter Oilseed, 3% Winter Wheat, 3% Spring Barley, 5%

Grassland, 33%

Non-vegetated or sparsely-vegetated Land, 13% Woodland, 31%

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Habitats Important habitats for wildlife are mapped below using Natural Englandâ&#x20AC;&#x2122;s Priority Habitat Inventory (PHI). Designated sites are also shown, with their condition status where relevant.

140 120

Area (ha)

100 80 60 40 20 0 Mudflats

D. Wood.

C&F Graz. Marsh

Trad. Orch.

No Main Hab

Anc. Woodland

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CEH Natural Capital Maps Natural England and UKCEH collaborated on a project to map aspects of natural capital. A suite of ten maps have been produced showing different aspects of natural capital, using a range of datasets, including UKCEH sample data from the Countryside Survey (2007). The maps are derived from predictive modelling. Data from sample locations is extrapolated up to an England level using statistical modelling and is mapped at 1km resolution. For more information: https://eip.ceh.ac.uk/naturalengland-ncmaps

Topsoil Carbon The map below shows mean estimates of topsoil (0-15cm depth) carbon density in tonnes per hectare. The map was produced using measurements of carbon from soil collected in the Centre for Ecology & Hydrology Countryside Survey (2007) at 2614 sample locations across Great Britain, within 591 1km squares. Measurements were extrapolated up to a national level using statistical analysis. This extrapolation was based on carbon density values associated with a combination of habitat type and soil parent material: the geological material, bedrock, superficial and drift, from which soil develops.

40 - 50 12%

70 - 80 88%

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Topsoil Nitrogen The map below shows mean estimates of total nitrogen concentration in topsoil (0-15cm depth) in percent dry weight of soil. The map was produced by using measurements of nitrogen concentration from soil collected in the Centre for Ecology & Hydrology Countryside Survey (2007), at 1024 sample locations across GB within 256 1km squares. Measurements were extrapolated up to a national level using statistical analysis. This extrapolation was based on total nitrogen concentration values associated with a combination of habitat type and soil parent material: the geological material, bedrock, superficial and drift, from which soil develops. < 0.25 12%

0.25 - 0.50 88%

Topsoil Phosphorous The map below shows mean estimates of Olsen-phosphorus concentration in topsoil (0-15cm depth) in milligrams per kg dry soil. This was calculated using the Olsen-phosphorus method, which is a measure of the amount of soil phosphorus available to plants. The map was produced by using measurements of Olsen-phosphorus from soil collected in the Centre for Ecology & Hydrology Countryside Survey (2007), at 1054 sample locations across GB, within 256 1km squares. Measurements were extrapolated up to a national level using statistical analysis. This extrapolation was based on phosphorus concentration values associated with a combination of habitat type and soil parent material: the geological material, bedrock, superficial and drift, from which soil develops. 40 - 50 12%

20 - 30 36%

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30 - 40 52%

Topsoil Invertebrates The map below shows mean estimates of total abundance of invertebrates in topsoil (0-8cm depth). This map was produced by using measurements of total number of invertebrates extracted from soil cores in the Centre for Ecology & Hydrology Countryside Survey (2007) at 927 sample locations across GB within 238 1km squares. Measurements were extrapolated up to a national level using statistical analysis. This extrapolation was based on the total number of invertebrates extracted associated with a combination of habitat type and soil parent material: the geological material, bedrock, superficial and drift, from which soil develops.

25 - 50 48%

50 - 75 52%

Topsoil Bacteria The map below shows mean estimates of bacterial diversity in topsoil (0-15cm depth) measured using the Shannon diversity index, a mathematical measure of species diversity in a given community. The map was produced by using measurements of bacterial diversity from soil in the Centre for Ecology & Hydrology Countryside Survey (2007), at 1280 sample locations across GB within 256 1km squares. Measurements were extrapolated up to a national level using statistical analysis. This extrapolation was based on soil bacterial diversity values associated with a combination of habitat type and soil parent material: the geological material, bedrock, superficial and drift, from which soil develops. 3.8 - 3.9 12%

3.6 - 3.7 43%

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3.7 - 3.8 45%

Land Ownership The map below shows anonymised land ownership data from the RPA CLAD dataset. Nonanonymised data will be available upon commencement of the work.

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River Condition The map below show Environment Agency Water Framework Directive overall status, category 1 and 2 water pollution incidents and consented discharges. The following pages give more information from the Catchment Data Explorer on WFD status, Reasons for Not Achieving Good status and upstream catchments. Note: Under the Water Framework Directive, waterbodies are given an overall status of High, Good, Moderate, Poor or Bad. Anything below Good is a failing waterbody.

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River Condition cont. This information has been sourced from the Catchment Data Explorer. The page for this waterbody is: https://environment.data.gov.uk/catchment-planning/WaterBody/GB108050020020

Knowl Water Overview Id

GB108050020020

Type

River

Hydromorphological designation

not designated artificial or heavily modified

Catchment area

1879.09 ha

Length

9.677 km

Classification Cycle 2 Classification Item

2013

2014

2015

2016

Overall Water Body

Moderate

Poor

Ecological

Moderate

Poor

Chemical

Good

Reasons for Not Achieving Good and Reasons for Deterioration SWMI

Activity