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Urban Rivers

Rivers have in many cases provided the resources and benefits necessary for the development of cities. Yet, in urban areas, rivers have often been seen as a threat to infrastructure and human health rather than as a resource, leading to their increasing degradation.

Many benefits that arise from protecting rivers and restoration projects can be similar to those from public parks where access is given and the restoration is designed to provide a similar environment, it can therefore be useful to refer to this factsheet to understand further benefits. Opportunities for river restoration in parks and other open spaces may also be more easily found than in higher density urban environments.

Access

Improved open spaces – in parks and other public open spaces, river restoration can improve their quality, as has been shown for example by the restoration project of the River Quaggy, running through Sutcliffe Park, where about 30% of the visitors only started visiting after the restoration project had improved the area, and 82% reported feeling differently in the park due to better recreational opportunities and higher biodiversity and the surrounding natural environment. Recreational opportunities are improved through increased opportunities for angling, water sports and low intensity activities. Improving pathways to enable active transport can have impacts on physical health. (1,2,3,4, 5,6,8,11)

Air Quality

Air quality is likely to be improved due to denser vegetation and the transport of fresh air along the river corridors – however this could also mean the distribution of pollutants from busy roads. (1,16, 17)

Pluvial Flooding

Draining landscapes into rivers rather than sewers could mean less risk of surface water flooding, however, it might increase flood risk from rivers. River restoration projects have to be carefully planned to accommodate for this function. Creation of floodplain and forest habitats increases runoff infiltration and so reduces the amount of water that needs to be drained away, with suitable natural habitat like medium dense woodlands and meadows likely reducing runoff by appr. 20%. (1, 4, 8, 13,19)

Fluvial Flooding

Restoring rivers, i.e. re-meandering them and establishing vegetation, creating wetlands, slows the flow and increases water storage capacity. It has to be understood where the issue is created (i.e., where does the water come from – upstream or surface water draining into the river?) and the correct measures have to be taken according to this. Erosion regulation can decrease the need for dredging downstream, reducing flood risk and also labour intensity. (1, 4, 8, 19)

Climate Regulation

Water bodies can have a cooling effect on their local area and so mitigate UHI effect. Wetlands and ponds that might be created through river restoration along with soils and vegetation can store carbon. The effect is size dependent (1, 15). In Seoul, daylighting of a a culverted river and vegetating the surrounding area has led to an average temperature of 14 degrees C lower than surrounding urban area (1, 4, 16).

Habitat Provision

Rivers are amongst the UK’s most diverse and rich ecosystem, and provide ecological connectivity through a landscape. Almost all rivers have been degraded. River restoration has been shown to improve the quality of water and habitat – an improvement of 1-3 classes in the WFD status compared to previous conditions has been found. Morphological status had also improved to moderate in almost half of the case studies, with a third even reaching “good” status (1,8, 9, 18)

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Water Quality

By allowing increased infiltration, trees improve water quality. Leaf litter on the ground reduces soil erosion, trees intercept pollutants and infiltrate them. Not much specific literature available.

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Low Flows

Depending on their characteristics, groundwater recharge can occur from rivers. Flow regimes are usually improved after restoration, although this depends on the type of restoration and the drivers of the flow regime. (1, 4)

Aesthetics

River landscapes are one of the most attractive landscapes, and this aesthetic quality provides many benefits by drawing people to the area. The effect on mental health has been described above and is also reflected in property values.

About 60% of the case studies evaluated in the 2004 URBEM report showed improvement of aesthetics after the river restoration project. (1, 2, 3, 4, 5, 6)

Cultural Activities

Reconnecting people to the natural environment (which in turn increases happiness) can be achieved by restoring natural landscapes in urban settings and making them accessible. This also increases the possibility to use them as educational resources, especially in urban settings where similar rural environments may not be as easily accessible. Water is connected to many activities that are not only recreational and benefit human health but also have cultural traditions connected to them, like angling or bird watching. At Mayesbrook Park (see case studies), the benefits from cultural service provision through restoration of an urban stream can be valued at £820,000 per year (1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13)

Property Values

View of water or a garden adjacent to water can have a significant positive impact on property values, with studies showing increases in value from 10% -even more than 30%. (1, 8, 18)

Flood Damage

Through their contribution to surface water drainage and regulating flows, healthy river ecosystems can help reduce severity of flooding.The Mayes Brook Restoration, for example, shows an annual benefit in improved flood management of £10,000. (4)

Considering the Bigger Picture

Rivers receive water as runoff from their surroundings, even more so due to the increasing impermeability of the urban environment. Sewers – meant to carry surface water flow, but often also carrying pollutants from misconnections – also discharge into watercourses. In addition, other pressures are present in the urban environment: air pollution from traffic can cause acidification.  Pesticides from roadsides or amenity areas can reach the water, as well as fertilisers. Construction sites can cause high sediment inflow. (Environment Agency 2009). Past culverting and straightening streams and disconnecting them from floodplains has also had a degrading impact.

To improve the state of urban rivers and restore the benefits they provide, there are many interventions that can be taken. Habitat can be restored, for example by removing hard riverbanks and re-meandering. Reducing runoff and pollution from hard surface by installing SuDS can improve water quality and work on a wider scale (7, 8, 19).

The costs for river restoration are very variable. A study on restoration projects carried out in the EU has shown that costs can range between 100 to 3000€ (equivalent to about 70-2300£) per metre of river restored (9). The cost of SuDS depends on their type.

Additional Benefits

 

 

(Mental) Health

water bodies have been found to be particularly significant in shaping people’s sense of place and improving their mental wellbeing. They provide attractive, stimulating features that have the ability to restore attentiveness and inspire creativity, and landscapes with water are perceived as more restorative than those without – even to the extent that urban landscapes featuring water are seen to be as restorative as green landscapes. Additionally, the improved recreational opportunities can give rise to increased social activities. Views of water and the sound of water have been shown to alleviate stress more effectively than other types of natural setting.

Economic

Improved sales – high quality environments lead to an increase in money spent in local businesses and also encourage businesses to settle in an area.

Employment – settlement of businesses in an attractive area can increase the local employment rate. Additionally, through the creation of parks new opportunities for businesses (cafes, outdoor recreation facilities) can improve the employment situation.

Social Cohesion

As restoration provides an opportunity for partnership working, the improved community ownership of places where restoration has been undertaken by an engaged community is likely to reduce crime and vandalism in the area (see “Access” and “Public Parks” factsheet) and increase the social connections between people living in the area.

  1. Maltby, E., Ormerod, S., Acreman, M., Blackwell, M., Durance, I., Everard, M., Morris, J., Spray, C. (2011) Freshwaters – Open Waters, Wetlands and Floodplains. In: The UK National Ecosystem Assessment Technical Report. UK National Ecosystem Assessment, UNEP-WCMC, Cambridge.
  2. van den Berg, M., Wendel-Vos, W., van Poppel, M., Kemper, H., van Mechelen, W. and Maas, J. (2015) ‘Health benefits of green spaces in the living environment: A systematic review of epidemiological studies’, Urban Forestry & Urban Greening, 14(4), pp. 806–816.
  3. Commission for Architecture and the Built Environment (2005) Decent parks? Decent behaviour?: The link between the quality of parks and user behaviour, pp.1–17.
  4. Everard, M. and Moggridge, H. L. (2012) ‘Rediscovering the value of urban rivers’, (April 2011), pp. 293–314.
  5. Jackson, R. J., Watson, T. D., Tsiu, A., Shulaker, B., Hopp, S. and Popovic, M. (2014) Urban River Parkways. Los Angeles.
  6. Nordh, H., Hartig, T., Hagerhall, C. M. and Fry, G. (2009) ‘Components of small urban parks that predict the possibility for restoration’, Urban Forestry & Urban Greening, 8(4), pp. 225–235.
  7. Palmer, M. A., Bernhardt, E. S., Allan, J. D., Lake, P. S., Alexander, G., Brooks, S (2005) ‘Standards for ecologically successful river restoration’, Journal of Applied Ecology, 42(2), pp. 208–217.
  8. RESTORE (2013) Rivers by Design. Bristol.
  9. Schanze, J., Olfert, A., Tourbier, J. T., Gersdorf, I. and Schwager, T. (2004) Existing Urban River Rehabilitation Schemes. Wallingford.
  10. Völker, S. & Kistemann, T., (2013) “I’m always entirely happy when I’m here!” Urban blue enhancing human health and well-being in Cologne and Düsseldorf, Germany. Social science & medicine (1982), 78, pp.113–24.
  11. White, M., Smith, A., Humphryes, K., Pahl, S., Snelling, D. and Depledge, M. (2010) ‘Blue space: The importance of water for preference, affect, and restorativeness ratings of natural and built scenes’, Journal of Environmental Psychology, 30(4), pp. 482–493.
  12. Zelenski, J.M. & Nisbet, E.K. (2012). Happiness and Feeling Connected: The Distinct Role of Nature Relatedness. Environment and Behavior, 46(1), pp.3–23.
  13. Sunderland, T. (2012) Microeconomic Evidence for the Benefits of Investment in the Environment – Review, Natural England Research Reports, Number 033.
  14. Environment Agency (2009) Water for life and livelihoods. River Basin and Management Plan Thames River Basin District. Annex G: Pressures and risks.
  15. Kayranli, B., Scholz, M., Mustafa, A. and Hedmark, Å. (2009) ‘Carbon Storage and Fluxes within Freshwater Wetlands: a Critical Review’, Wetlands, 30(1), pp. 111–124.
  16. Hathway, E. A. and Sharples, S. (2012) ‘The interaction of rivers and urban form in mitigating the Urban Heat Island effect: A UK case study’, Building and Environment, 58, pp. 14–22.
  17. Wood, C. R., Pauscher, L., Ward, H. C., Kotthaus, S., Barlow, J., Gouvea, M., Lane, S. E. and Grimmond, C. S. B. (2013) ‘Wind observations above an urban river using a new lidar technique, scintillometry and anemometry’, Science of the Total Environment. Elsevier.
  18. International Association of Certified Home Inspectors, Inc. (InterNACHI) (2016): Constructed Wetlands: The Economic Benefits of Runoff Controls.
  19. http://www.ecrr.org/RiverRestoration/UrbanRiverRestoration/tabid/3177/Default.aspx

 

More:

  1. http://www.urbem.net/index.html
  2. https://www.restorerivers.eu/