Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student Molly De Tine makes this connection here…

On January 23, 2014, the British Broadcasting Company (BBC) News featured an article on implementing natural dams to prevent flooding in England: Lord Rooker: ‘Planting trees could stop flooding’.  This article is in the hydrology domain and the specific issue encompasses movement of rainwater and flooding. In England, the countryside is designed to be visually appealing by encouraging rolling hills throughout the landscape. These hills however, create a flooding problem in nearby towns and villages. In order to reduce the frequency of flooding events the Environmental Agency and various other individuals and companies, headed by a former environment minister, Lord Rooker, have started a movement to use green infrastructure to delay runoff and reduce the amount of flooding. There are a number of different schemes implemented, including: natural dams such as trees across bodies of water; wooden fences along the edges of open fields; planting of trees in flood plains; and forcing runoff into pipes and catching overflow behind a steel wall. According to Marshall et al. (2013) and Ballesteros-Caovas et al. (2013), as well as my engineering education and informed opinion, this news article is accurate. Marshall et al. (2013) states that planting vegetation near stream beds decreases the potential of downstream flooding. Through research, it was also shown that felling trees across waterways and other flood prevention techniques, such as walls, prove to be an efficient way to slow down water and reduce downstream flooding (Ballesteros-Canovas et al., 2013). It would have beneficial if this article included quantifying results of how much the green infrastructure affects the flood levels. Also, the article did not state how the location is decided where the dams and other various structures are placed.

This article shows how the domain of hydrology can impact a broad economical context, these are the problems caused by hydrology concerns that affect monetary dealings. The referenced floods bring about many repairs on infrastructure, houses, buildings, and equipment which can be economically inefficient. According to Xiao et al. (2011), floods can cause millions of dollars in damages of properties. Since dams and walls have been constructed on certain streams and other bodies of water, there has been no financial activity due to floods in the nearby towns. This hydrology domain also affects surrounding communities and people, which are part of the societal context area. The streams in the UK were flooding villages with lower elevations of nearby streams and other various bodies of water. The villages downstream of the manmade, natural dams have had a significant decrease in floods since the infrastructures were constructed.

A barrier wall constructed to keep the water from the open field from flooding the stream nearby and the village downstream.

A barrier wall constructed to keep the field runoff from rapidly entering the stream and flooding the village downstream.

The trees placed over water upstream to villages do not affect the flow of water during normal conditions. This dam floods the water upstream so flooding in avoided in nearby villages.

The trees placed over the stream so upstream to villages have less effect on flow during normal conditions. This dam increases water depths upstream to minimize flooding in nearby villages.

References:

Ballesteros-Canovas JA, Sanchez-Silva M, Bodoque JM, Diez-Herrero. An Integrated Approach to Flood Risk Management: A Case Study of Navaluenga (Central Spain). Water Resources Management. 2013; 27:3051-3069.

Marshall MR, Ballard CE, Frogbrook ZL, et al. The impact of rural land management changes on soil hydraulic properties and runoff processes: results from experimental plotsin upland UK. Hydrological Processes. 2013; 28:2617-2629.

Xiao Y, Wan J, Hewings GJD. Flooding and the Midwest economy: assessing the Midwes floods of 1993 and 2008. GeoJournal. 2011; 78:245-258.

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