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Landscape planning for floods: from river engineering to river reclamation

Rivers Policy

  1. A major reclamation programme is necessary to reclaim our 'channels', 'water-courses', 'culverts' and 'coastal defences'. Their dignity must be restored, as streams, brooks, rivers and shores. 
  2. Landscape character plans should be formulated. 
  3. Rainwater should be infiltrated near to where it falls - or else it should detained near to where it falls, and discharged slowly. 
  4. Rivers and coasts should be planned, designed and managed. In places, this will require no human intervention: the coast should be as natural as possible. In other places, their scenic and recreational potential should be developed. Rivers and coasts have exceptional scope for contributing to a green web of public open space. 
  5. Negative environmental impacts should be mitigated. 
  6. Positive environmental impacts should be planned and designed.  Waterfront land is our most valuable land.

The illustration, right, was placed on this web page c2005 and since that date a major river reclamation project for the Rio Manzanares river reclamation has been launched. Gardenvisit.com does not take the whole credit for this initiative! West 8 are helping with the design work.

Where are the streams of yesteryear? Underground. (Whyte 1970: 362)

Those streams of yesteryear will have to be reclaimed. They lie imprisoned in underground culverts or restrained by concrete walls and artificial embankments. Because wild nature is everywhere under threat, we want our rivers back. Drainage works and impermeable surfacing continue apace. Unless drastic action is taken, all the rivers in the all the urban regions of all the industrialised countries will be lost. This drawing shows the 'lost rivers of London'.

  • Flood prevention: Floods induce fear - and high expenditure.
  • Forest clearance: Forest clearance accentuates flooding.

A forest can absorb rainwater, like a great sponge, and help it run into the ground. This benefit is removed when the forest is removed. The current plight of Bangladesh is a tragic example (Khalil, 1993). At one time there were great swamps and forests in the foothills of the Himalayas. Malaria kept humans out. After the introduction of anti-malarial drugs, the forest was cleared and the rate of run-off greatly accelerated. Periodically, this causes terrible floods and loss of life in Bangla Desh [Fig 9.2]. The developed countries which have removed their forests have also increased their liability to flooding. Axemen have no interest in EID.

  • Agricultural drainage: Farm drainage accentuates flooding.
  • Urban drainage: Urban drainage accentuates flooding.
  • River works in Britain: River improvement accentuates flooding.
  • Present conditions: The flood problem has been accentuated.

River reclamation And he shewed me a pure river of water of life, clear as crystal, proceeding out of the throne of God and of the Lamb. (Bible Ch 22 v 1, Revelation of St John the Divine)

In the past, 'improving' rivers meant increasing their flow capacity. In future it should refer to multi-purpose schemes designed to improve the capacity of each river valley to function as a visual amenity, a recreation area, a fishery, a nature reserve, a water supply, a storm detention area, a drainage network, and a movement corridor for boats, walkers, cyclists and equestrians. We are fortunate that the means have become available:

  1. Multi-purpose planning Rivers can do more than carry water.
  2. Managed flooding Flood risk can be managed.
  3. Storm detention Storm water should be detained.
  4. Rainwater infiltration Storm water should be infiltrated.
  5. Vegetated roofs Vegetated roofs decrease flooding.
  6. Porous pavements Porous pavements decrease flooding.
  7. Natural riverworks Bio-engineering is better.

Robert Louis Stevenson wrote:

Dark brown is the river,
Golden is the sand.
It flows along for ever,
With trees on either hand       (R L Stevenson, Where go the boats)

  • River control structures: River structures should serve many objectives.
  • Coastal defence: Coasts need landscape plans.
  • Conclusion We must win our rivers back.

After centuries of 'improving' rivers and 'defending' coasts against floods, the developed countries have given their waterfronts a military aspect, dominated by embankments, retaining walls, and concrete ditches. A major reclamation programme is necessary to reclaim our 'channels', 'water-courses', 'culverts' and 'coastal defences'. Their dignity must be restored, as streams, brooks, rivers and shores.

At some happy point in the future, it may become possible to follow the melancholy book on The lost rivers of London (Barton 1962) with a triumphalist sequel: How we won back London's rivers.

 

Links

Open Directory section on River Restoration

Refs

Barton, N. 1962. The lost rivers of London. London:Pheonix House.

Dunne, T. & Leopold, L.B. 1978. Water in environmental planning. San Francisco: W.H. Freeman

Brookes, A. 1988. Channelized rivers: perspectives for environmental management. Chichester:John Wiley.

CIRIA 1992a. Report 124: Scope for control of urban runoff Volume 2: A review of present methods and practice. London:Construction Industry Research and Information Service.

CIRIA 1992b. Report 124: Scope for control of urban runoff Volume 3:Guidelines London:Construction Industry Research and Information Service.

Gardiner, J.L. 1994. Sustainable development for river catchments. Water and environmental management Vol 8 No 3.

Glitz, D. 1983. Artificial channels - the 'ox-bow' lakes of tomorrow. Garten & Landschaft. February pp 109-111.

Hall, M.J. 1984. Urban hydrology. Amsterdam Elsevier.

Nixon, M. 1966. Flood regulation and river training. In Thorn, R.B. River engineering and water conservation works. London:Butterworth.

Turner, T, Landscape planning and environmental impact design. London:UCL Press 1998 Chapter 9

Medium manzanares river madrid original

The River Manzanares, in
Madrid, awaits reclamation.