hydraulic habitat modelling and mapping - david mould, jba consulting
TRANSCRIPT
Hydraulic Habitat Modelling and MappingDave Mould
Structure
• What is hydraulic habitat modelling and mapping?
• Hydraulic modelling (in 2 slides……)
• 3 case studies
– As part of the design process
– Investigation tool to build evidence
– Impartial appraisal
• Summary
Hydraulic habitat
The combination of river depth, velocity and substrate determines the available physical habitat for aquatic species.
Therefore, hydraulic models can then be used in combination with knowledge of the habitat requirements of species/life stage of interest to determine habitat availability. Can also inform on sediment dynamics.
1D modelling
Max vel
Island
2D modelling
APR Project 15. Two dimensional modelling in Urban and Rural Floodplains
Case study 1 - Design
Case study 1 - Design
Case study 1 - Design
Case study 1 - Design
Case study 1 - Design
Case study 2 – Evidence
EA science project SCSC0120077
Case study 2 – Pershore weir
Case study 2 – Evidence
Q95 Depth. On-weir HEP Q95 Depth. Depleted reach Q95 Velocity. On-weir HEP Q95 Velocity. Depleted reach
Difference = post installation minus pre installation.
Case study 2 – Evidence
Q20 Depth. On-weir HEP Q20 Depth. Depleted reach Q20 Velocity. On-weir HEP Q20 Velocity. Depleted reach
Difference = post installation minus pre installation.
Case study 3 - Appraisal
Pool and run
Shoulder
Vegetation management
Case study 3 - Appraisal
Case study 3 - Appraisal
Case study 3 – Pool and run Pre change adult Brown Trout habitat Post change adult Brown Trout habitat
Pre change Brown Trout spawning habitat Post change Brown Trout spawning habitat
Run
Pool
Run
Pool
Run
Pool
Run
Pool
Case study 3 - Shoulder
Pre-change 0+ Cyprinid habitat Post-change 0+ Cyprinid habitat
Case study 3 – Veg removal Pre-change 0+ Cyprinid habitat Post-change 0+ Cyprinid habitat
Pre-change Brown Trout spawning habitat Post-change Brown Trout spawning habitat
Case study 3 – Crisp summary
Total Habitat Suitability (THS) Q95 Q70 Q50 Qmean Q10
Adult BT 2665 4085 4495 4761 5178 1+ BT 2685 3689 3939 4318 5247
0+ BT 4798 5011 4559 3913 2197 BT Spawning 2791 3523 4202 4698 5360
0+ Cyp 862 1568 1596 1607 2019
Habitat Quality Q95 Q70 Q50 Qmean Q10
Adult BT 26 32 35 36 37
1+ BT 26 29 31 33 38 0+ BT 47 40 36 30 16 BT Spawning 27 28 33 36 39 0+ Cyp 8 12 12 12 15
Summary
Pros ConsAcross whole flow regime and range of species/life stages.
Cost of survey data vs scale of the modelling
Spatial & crisp outputs Often limited knowledge of requirements of many species
Results in a data poor situation Uncertainty in model results
Play tunes with model topography
Optimisation of designs