Toby Hull South East Rivers Trust March 2015 The Constraints of Connecting Habitat and Fish Passage in an Urban Environment

Outline Introduction to the Hogsmill River Introduction to the CRF Project Constraints encountered with the project (challenges) Solutions and Outcomes (opportunities) Conclusion

Hogsmill River -Urban catchment in South London -Joins the Thames at Kingston -1 st non-tidal tributary of the Thames -6.5 miles long -Technically a chalk stream (but flashy urban characteristics) -Poor water quality -Appeared in Millais’ “Ophelia”

Hogsmill River

-Highly modified channel -15 obstructions between the source in Ewell and the Thames at Kingston -Fragmenting already heavily degraded habitat -WFD status – Poor with Fish and Macrophytes driving classification

CRF Hogsmill River Connectivity Project Aim: To provide fish passage along the entire river in order to improve WFD status towards achieving Good Ecological Potential (GEP) Objective: Removal or modification of all obstructions/barriers to passage and connectivity £350k

Flood Defence & Historic Relics

Bridge Footings

Utilities

Spatial Constraints

Spatial & Flood Risk Constraints

Gauging Data

“if it can be thought, it can be done, a problem can be overcome” E. Bucchianeri, Brushstrokes of a Gadfly Where there’s a will (& some money) there’s a way…

Different solutions, different ways of delivering: Contractors, in-house, volunteers

Flood Risk (real or perceived) Surrounding Land Use Utilities Bed & Bank Stabilisation Migrating Knick-Points

Constraints = Compromise

Rock Ramp

Concrete

Before Close-to-Nature Pool Pass After

Baffles

Composite Solution

Additional Benefits

Habitat Improvements Flood Risk Reduction Water Quality Improvements Partnership Working Community Interest

Additional Benefits

Lessons Learnt

“There are no secrets to success. It is the result of preparation, hard work and learning from failure” Colin Powell “Failure is success if we learn from it” Malcolm Forbes

Summary There are a lot of constraints…

Irremovable Structures Utilities/Services Surrounding Land Use Spatial Channel Morphology Flood Risk Access River Characteristics (flow regime) Working ‘wet’ in-channel Weather Knowledge Public Perception (‘waterfalls’) Flood Risk (perceived) Fish Swimming Capabilities Time Data Collection Budgets Infrastructure

Summary There are a lot of constraints… But persevering, we’ve always found a solution, even if there is compromise This may mean that we concentrate on fish passage and not full connectivity but this does move the river towards GEP (being as good as it can be within the constraints). We’ve learnt a lot along the way and have had lots of help from others Also had lots of fun along the way!

Thank you for your attention