Results from the Defra funded Mitigation Options for Phosphorus and Sediment (MOPS2) project

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1 Intercepting Diffuse Pollution Pathways: or Small farm wetlands trap sediment, nutrients and carbon John Quinton, Mary Ockenden and Clare Deasy Lancaster Environment Centre Results from the Defra funded Mitigation Options for Phosphorus and Sediment (MOPS2) project Undertaken by Lancaster University, ADAS, the Game & Wildlife Conservation Trust & the University of Reading

2 Outline Preventing the mobilisation of diffuse pollutants is always a good idea If that doesn t work then intercepting runoff pathways can be a very good back up plan

3 Reduces sediment loss by 16 94% Reduces TP loss by 9 97% Reduces TN loss by 30 97% Cost at farm scale 2 to 5 per ha Reduces sediment loss by 37 98% In field Barriers Reduces sediment loss by 75 99% Reduces TP loss by 75 99% Reduces TN loss by 75 99% Cost at farm scale 2 to 5 per ha Minimum Tillage Tramline Management MOPS1: Results Reduces sediment loss by 40 43% Reduces TP loss by 34 50% Reduces TN loss by 37 56% Crop Cost at farm Residue scale 0 per ha Incorporation Reduces sediment loss by 45 79% Reduces TP loss by 29 97% Reduces TN loss by 26 94% Cost at farm scale + 44 to + 50 per ha Contour Cultivation Reduces TP loss by 48 79% Reduces TN loss by 63 71% Cost at farm scale 0 per ha

4 MOPS2 Ponds & Wetlands 10 Field wetlands created on 4 farms: 3 soil types (sand, silt, clay) 3 designs (shallow single, shallow paired, deep and shallow paired) 3 sizes (25, 50 or 100 m 2 for every 10 ha land) Different runoff sources (surface runoff, drains, ditches and streams) Water quality and sediment and nutrient retention monitored Socio economic factors considered including cost analysis, farmer questionnaires & focus groups Field wetland: Small constructed wetland located in an unproductive area of agricultural land, designed to trap sediment and nutrients from runoff pathways

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6 MOPS2 UK Research Sites Newton Rigg, Cumbria Soil texture: silt Annual rainfall: 950 mm Land use: arable 1 wetland Whinton Hill, Cumbria Soil texture: sand Annual rainfall: 950 mm Land use: arable/grazing 3 wetlands Crake Trees Manor, Cumbria Soil texture: silt Annual rainfall: 1150 mm Land use: arable/grazing 3 wetlands Loddington, Leicestershire Soil texture: clay Annual rainfall: 650 mm Land use: arable 3 wetlands

7 Shallow Single Cell Shallow Paired Cell Deep and Shallow 10 MOPS2 Field Wetlands Paired Cell Clay 20m2 100m2 20m2 Silt 5m2 125m2 200m2 50m2 Drain 50m2 7.5m2 320m2 Sand

8 Field wetlands are often located in unproductive field areas, field corners, alongside or in ditches, and in buffer strips Upper Ponds field wetland, Loddington, located in a field corner

9 India field wetland located instream

10 Field Wetland Creation Features can be created quickly using on farm machinery or by bringing in contractors Field wetlands are ideally located in unproductive field areas, field corners, alongside or in ditches, and in buffer strips Shallow ponds vegetate naturally over several years Features can be created quickly using on farm machinery or by bringing in contractors Excavating Shelduck field wetland in a boggy field

11 Shallow ponds vegetate naturally over several years Upper Ponds field wetland after construction

12 Upper Ponds field wetland two years after construction

13 Vegetation in Bill and Ted field wetland three years after construction

14 BUT DO THEY WORK?

15 Sediment Accumulation Sediment accumulation determined from annual surveys

16 Annual Sediment Accumulation Whinton Hill Cumbria (sand) t yr 1 sediment including kg yr 1 TP kg yr 1 TN Crake Trees Cumbria (silt) 4 18 t yr 1 sediment including 2 10 kg yr 1 TP kg yr 1 TN Loddington Leicestershire (clay) t yr 1 sediment including kg yr 1 TP 1 3 kg yr 1 TN

17 Water Quality Sampling at Whinton Hill From field drains, including wastewater input ditch Yellowhammer Catchment area: 30 ha Shelduck ditch to river Gully Trap 1 YHin 2 YHout 3 SDin 4 SDmid 5 SDout Surface runoff directed towards Gully Trap Fortnightly manual sampling at points 1, 2, 3, 4 and 5 Analysis: SS TP, TDP, SRP TN, TDN, NO 3 N, NO 2 N, NH 4 N (not to scale) Daily composite sampling at points 3, 4 and 5 Analysis: SS TP TN

18 TP 75% reduction TDP 90% reduction SRP 95% reduction TP 65% reduction TDP 80% reduction SRP 80% reduction Concentration mg l Concentration mg l YHin YHout SDin SDmid SDout 0 YHin YHout SDin SDmid SDout TN -55% TDN -60% N0 3 -N -35% NH 4 -N -75% TN -50% TDN -60% N0 3 -N +5% NH 4 -N -75% Concentration mg l Concentration mg l YHin YHout SDin SDmid SDout 0 YHin YHout SDin SDmid SDout

19 Conclusions Field wetlands are useful, practical features to be considered as part of a toolkit for mitigation of diffuse pollution from agriculture Sediment trapping was highest at a sandy site (25 40 t yr 1 ), compared to a silty site (4 20 t yr 1 ) and a clay site (0.3 1 t yr 1 ) Average P and N concentrations were reduced between inlet/outlet, for both particulate associated nutrients and dissolved nutrients

20 Further Information Acknowledgements: Funding received from Defra WQ0127 Assistance received from laboratory and technical staff at Lancaster University and the Allerton Project Farms involved: Crake Trees Manor Farm, Cumbria; Brackenburgh Home Farms, Cumbria; Sewborwens Farm, Cumbria; The Allerton Project, Loddington, Leicestershire; The Lancaster team : Mary Ockenden, Clare Deasy and Anna Ola, Guidance Available Policy Guidelines Field Wetland Construction Guidelines For more information, please view our website: mops2.diffusepollution.info