wetland land use management at whole catchment scale (wp5.3 and wp5.4)
DESCRIPTION
Wetland Land Use Management at Whole Catchment Scale (WP5.3 and WP5.4). Professor Ian Cluckie College of Engineering Swansea University. Run off / Wash off. Soil & Mud Flow. Soil Compaction. Wetland Land Use Management at Whole Catchment Scale – WP5.3. - PowerPoint PPT PresentationTRANSCRIPT
Wetland Land Use Management at Whole Catchment Scale
(WP5.3 and WP5.4)
Professor Ian CluckieCollege of Engineering
Swansea University
1
Whole Catchment Modelling Project- Technical Report -
October 2006
Jongsook Park & Ian D. CluckieWEMRC
(Water & Environmental Management Research Centre)
Wetland Land Use Management at Whole Catchment Scale – WP5.3
The Parrett and Tone catchments – Large floods in 1999 and 2002DHI MIKE SHE Model
Soil & Mud FlowSoil & Mud Flow
Soil CompactionSoil Compaction
Run off / Wash offRun off / Wash off
Human Activities and Soil3
• Soil degradation increased by heavy machinery or soils worked in wet conditions• Cultivated land, winter cereal crops, more degraded than permanent grass, but it
varies with the degree of slope
Land Use
Bare soil: harvest ~ before seeding
0
20
40
60
80
100
120
140
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average SMD
SMD (2001)
SMD (1999)
SMD (2000)
SMD (2002)
Average Soil Moisture Deficit (1961 ~ 2000)
If soil moisture is at optimum levels during the soil cultivation periods of the autumn and spring the
risk of soil degradation occurring is limited
Flood Impact Downstream?
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• LAND USE Change had relatively LITTLE impact at Whole Catchment Scale
• FLOOD retention STORAGE MORE EFFECTIVE at decreasing flood volume and peak, but varied by sub-catchment
• Large Catchment dominated by CHANNEL NETWORK
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Lowland SedimentsWP5.4 - Tone Catchment Case Study
• Sediment delivery to rivers is likely to be exacerbated by future climate change
• Uncertainty how sediment drives changes in morphology and flood risk in lowland rivers – Highly Event Driven
• RBMP & CFMP targets & activities must not conflict, and preferably support each other
Sediment Issues:
contact: [email protected]
1.1. Wash load sedimentWash load sediment can alter morphology in key locationscan alter morphology in key locations
2.2. Water level and inundation patterns likely to be affected, but Water level and inundation patterns likely to be affected, but flood risk flood risk impacts may be minimalimpacts may be minimal
3.3. River sediment management (receptor) may be restricted to River sediment management (receptor) may be restricted to local ad hoclocal ad hoc intervention to maintain flood defence assets or intervention to maintain flood defence assets or other uses – e.g. Dredgingother uses – e.g. Dredging
4.4. Catchment sediment management (source) likely to be driven Catchment sediment management (source) likely to be driven by by WFDWFD & & Soil Resource Protection Soil Resource Protection rather than rather than FRMFRM
5.5. Areas of Areas of uncertaintyuncertainty include defining include defining sedimentsediment yieldyield and and understanding understanding temporaltemporal position in a river regime position in a river regime
Key Messages
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• The impact of land Use Management was NOT significant at Whole Catchment Scale – FLOODPEAK and VOLUME
• However ,was important at plot and Field Scale!
• Space/time scaling effects are still not completely understood BUT dominance of Channel Network primary control on Flood Impact on Large Catchments
• Land Use Change had greater impact on Sediment, Bio-Diversity, Water Quality and Landscape rather than flood peak or volume
• FRM still important but NOT Panacea!