Surface Water Management https://coastal-management.eu/ en EXAMPLE: Constructed wetlands to compensate for urbanization in souther Finland (FIN) https://coastal-management.eu/measure/example-constructed-wetlands-compensate-urbanization-souther-finland-fin <span class="field field--name-title field--type-string field--label-hidden">EXAMPLE: Constructed wetlands to compensate for urbanization in souther Finland (FIN)</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="https://coastal-management.eu/user/6" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">nst</span></span> <span class="field field--name-created field--type-created field--label-hidden">Thu, 02/16/2017 - 10:00</span> <div class="field field--name-field-adressed-disks field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/52" hreflang="en">Flash floods</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/54" hreflang="en">Urban floods</a></div> </div> <div class="field field--name-field-type-of-measure field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/61" hreflang="en">Surface Water Management</a></div> </div> <div class="field field--name-field-colour field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/65" hreflang="en">Ecosystem based approach</a></div> </div> <div class="clearfix text-formatted field field--name-field-short-descr field--type-text-long field--label-hidden field__item"><p>In Finland urban wetlands are being implemented to help improve water quality, absorb storm water volume and flow control, and improve the land-water habitats for urban communities. The wetlands are designed to respond to the needs and negative impacts of urbanization and therefore, public acceptance and multifunctional benefits are central to the design and implementation of the wetlands. The acceptance and understanding of the importance of urban dwellers is important and thus the project sought to demonstrate several benefits of functional wetlands.</p></div> <div class="clearfix text-formatted field field--name-field-information-source field--type-text-long field--label-hidden field__item"><p>Based on Wahlroos et al. (2015): <span><a href="http://www.tandfonline.com/doi/full/10.1080/21513732.2015.1006681">Urban wetland parks in Finland: improving water quality and creating endangered habitats</a>. In: </span> <span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Urban wetland parks in Finland: improving water quality and creating endangered habitats</span></span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">. In: International Journal of Biodiversity Science, Ecosystem Services & Management Volume 11, Issue 1: Pages 46-60</span></p> <p> </p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h4>General description</h4> <p>Urbanization is affecting water quality and there is increasing severity of flooding and drought periods in Southern Finland. This is expected to become worse because of climate change. During flooding events, run off from rain and melting snow are quickly carried over urban surfaces and overwhelm receiving streams. Habitat degradation is occurring as harmful water from urban areas is transferred into connected habitats. These urban streams in turn cause flooding and channel erosion. The creation of wetlands is an alternative ecosystem approach to conventional responses that have been to seal natural waterways into culverts or clearing, and stabilization for augmented conveyance and erosion control. </p> <p>Two urban wetlands, the Nummela Gateway and the Nummela Niittu were designed and implemented. The wetlands are 6ha and 7ha respectively and are within 550 ha of the urbanized Kilsoi stream watershed in the catchment of Lake Enäjärvi, in the Nummela community, Municipality of Vihti, Southern Finland. The lake has poor water quality from algal blooms and fish kills that result from runoff from its catchments and phosphorus load from human activities. The Stream Kilsoi is an inland clay-soil stream that drains into the Baltic Sea. The habitat type and clay-stream is red listed in the Red list Assessment of Finnish habitat types as critically endangered.</p> <h4>Ecosystem-based aspects</h4> <p>The creation of wetlands is an ecosystem approach and replaced hard infrastructure and conventional responses that have previously been implemented in the area to control storm water volume. In the past, the convention has been to seal natural waterways into culverts or clearing, and stabilization for augmented conveyance and erosion control. </p> <p>The two wetlands, Nummela Gateway and the Nummela Niittu, were established over five years and closely monitored. The ecosystem service that was deemed most important for the wetlands to provide was water quality management. Water treatment by wetlands depends on the plants and their associated microbes. Storm water and flooding events are the main carriers of potential pollutants from urban areas, and thus a high density and diversity of plans and microbes is necessary. In this case, the native origin of the plants was also found to be important to protect urban streams from the erosive effects of storms and snowmelts. Plant self-establishment occurred quickly and construction only required the monitoring of water levels, especially during winter. The existing shoreline and old drainage ditches acted as a seedbank and no maintenance of native plants was necessary.</p> <p>In addition to improving biodiversity, water quality improvements were also achieved. There was an increase in phosphorus reduction after the third year. Despite that the Gateway wetland is just 0.1% of its 550 ha watershed area, it does achieve an annual 10% for total phosphorus reduction.</p></div> <div class="clearfix text-formatted field field--name-field-key-lessons field--type-text-long field--label-above"> <div class="field__label">Key lessons learnt</div> <div class="field__item"><p>The establishment of two wetlands near to an urbanized area was able to mitigate against various challenges stemming from urbanization. The Gateway and Niittu wetlands were successful in creating high biodiversity at the clay-stream habitats and relied on little human maintenance due to the naturally occurring habitat which was conducive to wetland creation and existence.</p> <p>Some compromises were made in order to ensure the acceptance of the wetlands and their appreciation and support by the community. Both wetlands were designed to accommodate open water areas for recreational purposes and thus do not fulfill the most efficient capacity for pollution removal.</p> <p>Despite the establishment of the wetlands, they do not address source control directly which remains an issue. If action is taken to reduce pollution at the source, then the wetlands will be more productive in response.</p> <p>Continued monitoring during and after the establishment of the wetlands allowed for there to be definitive conclusions on the impact of the created wetlands on water pollution mitigation, self establishment of vegetation, and biodiversity development. Water quality improvements were demonstrated with continuous monitoring which would not have been deciphered via discrete water sampling.</p></div> </div> <div class="field field--name-field-relevant-case-studies-and- field--type-entity-reference field--label-above"> <div class="field__label">Relevant case studies and examples</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/measure/wetland-restoration" hreflang="en">Wetland restoration</a></div> </div> </div> <div class="clearfix text-formatted field field--name-field-literature-sources field--type-text-long field--label-above"> <div class="field__label">Literature sources</div> <div class="field__item"><h5><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US"><strong>Main source: </strong>Outi Wahlroos, Pasi Valkama, Emmi Mäkinen, Anne Ojala, Harri Vasander, Veli-Matti Väänänen, Anna Halonen, Leena Lindén, Petri Nummi, Hannele Ahponen, Kirsti Lahti, Teuvo Vessman, Kari Rantakokko & Eero Nikinmaa (2015): </span><a href="http://www.tandfonline.com/doi/full/10.1080/21513732.2015.1006681"><span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Urban wetland parks in Finland: improving water quality and creating endangered habitats</span></span></a><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">. In: International Journal of Biodiversity Science, Ecosystem Services & Management Volume 11, Issue 1: Pages 46-60</span></h5></div> </div> <div class="field field--name-field-measure-category field--type-entity-reference field--label-above"> <div class="field__label">Measure category</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/76" hreflang="en">Mitigation</a></div> </div> </div> Thu, 16 Feb 2017 09:00:50 +0000 nst 293 at https://coastal-management.eu EXAMPLE: The Ekostaden Augustenborg initiative, Malmö (SWE) https://coastal-management.eu/measure/example-ekostaden-augustenborg-initiative-malmo-swe <span class="field field--name-title field--type-string field--label-hidden">EXAMPLE: The Ekostaden Augustenborg initiative, Malmö (SWE)</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="https://coastal-management.eu/user/6" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">nst</span></span> <span class="field field--name-created field--type-created field--label-hidden">Thu, 01/26/2017 - 16:19</span> <div class="field field--name-field-adressed-disks field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/54" hreflang="en">Urban floods</a></div> </div> <div class="field field--name-field-type-of-measure field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/61" hreflang="en">Surface Water Management</a></div> </div> <div class="field field--name-field-colour field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/66" hreflang="en">Combined approach (grey + green)</a></div> </div> <div class="clearfix text-formatted field field--name-field-short-descr field--type-text-long field--label-hidden field__item"><p>Augustenborg is a highly populated neighbourhood in Malmö, Sweden. In order to minimise flood risk, between 1998 and 2002, the ‘Ekostaden Augustenborg’ initiative installed a ‘Sustainable Urban Drainage System’ (SuDS). As part of the project, green roofs, ditches, retention ponds, green spaces and wetlands were created. Due to the installation of the SuDS, rainwater run-off has decreased by half.</p></div> <div class="clearfix text-formatted field field--name-field-information-source field--type-text-long field--label-hidden field__item"><p>Based on RECREATE project results: <a href="http://ec.europa.eu/environment/integration/green_semester/pdf/Recreate_PB_2015_NBS_final_druck10-02-2016.pdf">COASTAL PROTECTION AND SUDS – NATURE-BASED SOLUTIONS</a>.</p> <p> </p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h4>General description</h4> <p>The neighbourhood Augustenborg in south-western part of Malmö (Sweden) suffered from floods caused by overflowing drainage systems. Resulting flooding was leading to damage to underground garages and basements, and restricted access to local roads and footpaths. In order to minimise flood risk, between 1998 and 2002, the ‘Ekostaden Augustenborg’ initiative installed a “Sustainable Urban Drainage System” (SuDS). The project was carried out collaboratively by the city council and the MKB social housing company, with extensive participation of the residents in Augustenborg. As part of the project, green roofs, ditches, retention ponds, green spaces and wetlands were created. Due to the installation of the SuDS, rainwater run-off has decreased by half. Additional benefits include improved water quality, reduced carbon emissions, aquifer recharge (relieving stress in water scarce areas), and increased biodiversity through the creation of new wetland habitats.</p> <p>As the project involved significant physical changes in infrastructure, a main challenge was to ensure the acceptance of the local residents. An extensive and iterative process of stakeholder engagement was also initiated during the design and execution of this project, involving a ‘rolling programme’ of consultation with local residents, representatives from the local school, practitioners, city staff and local businesses. The physical improvements in Augustenborg and related projects totaled approximately 21 million Euro. About half of the funds were invested by the MKB housing company. Without the partnership between resident companies and public authorities, the funding for this project would not have been sufficient.</p></div> <div class="field field--name-field-relevant-case-studies-and- field--type-entity-reference field--label-above"> <div class="field__label">Relevant case studies and examples</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/measure/sustainable-urban-drainage-systems-suds" hreflang="en">Sustainable Urban Drainage Systems (SUDS)</a></div> </div> </div> <div class="field field--name-field-further-readings field--type-link field--label-above"> <div class="field__label">Further Readings</div> <div class="field__items"> <div class="field__item"><a href="http://www.forestry.gov.uk/pdf/urgp_case_study_015_Malmo.pdf/$FILE/urgp_case_study_015_Malmo.pdf">Case Study description from Forest Reseach (UK)</a></div> </div> </div> <div class="clearfix text-formatted field field--name-field-literature-sources field--type-text-long field--label-above"> <div class="field__label">Literature sources</div> <div class="field__item"><p>Kenna Davis, Ina Krüger & Mandy Hinzmann (2015): <a href="http://ec.europa.eu/environment/integration/green_semester/pdf/Recreate_PB_2015_NBS_final_druck10-02-2016.pdf">COASTAL PROTECTION AND SUDS – NATURE-BASED SOLUTIONS</a>. Recreat Policy Brief No. 4, November 2015, 14 p</p> <p> </p></div> </div> <div class="field field--name-field-measure-category field--type-entity-reference field--label-above"> <div class="field__label">Measure category</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/76" hreflang="en">Mitigation</a></div> </div> </div> Thu, 26 Jan 2017 15:19:26 +0000 nst 281 at https://coastal-management.eu Rainwater harvesting https://coastal-management.eu/measure/rainwater-harvesting <span class="field field--name-title field--type-string field--label-hidden">Rainwater harvesting</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="https://coastal-management.eu/user/6" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">nst</span></span> <span class="field field--name-created field--type-created field--label-hidden">Fri, 12/02/2016 - 12:05</span> <div class="field field--name-field-adressed-disks field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/53" hreflang="en">Riverine or slow rise floods</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/52" hreflang="en">Flash floods</a></div> </div> <div class="field field--name-field-type-of-measure field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/61" hreflang="en">Surface Water Management</a></div> </div> <div class="field field--name-field-colour field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/66" hreflang="en">Combined approach (grey + green)</a></div> </div> <div class="clearfix text-formatted field field--name-field-short-descr field--type-text-long field--label-hidden field__item"><p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Water harvesting is when rainwater or stormwater is collected and stored for productive use later. It can be used for agriculture, drinking and more. Historically, rainwater harvesting is a common practice and has been used by many communities to support agriculture in sensitive and variable climates. </span></p></div> <div class="clearfix text-formatted field field--name-field-information-source field--type-text-long field--label-hidden field__item"><p><a href="http://web.unep.org/ecosystems/sites/default/files/uploads/resource/file/Green%20infrastructure%20Guide.pdf">Based on kindly provided information by UNEP's "Green Infrastructure Guide for Water Management: Ecosystem-based Management Approaches to Water-related Infrastructure Projects " (UNEP, 2014)</a></p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">As a result of its widespread and historical use, many varieties of harvesting water exist and depend on the area available for catchment as well as the intended post-collection use. Water harvesting techniques can be divided in two main types: <strong>in situ</strong> and <strong>ex situ</strong>.</span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">In situ rainwater harvesting is a technique that increases the capacity of the soil to store water, thus collecting water where it lands. In situ collection ensures that rainwater remains where it falls with little distance between capture and usage areas. Some examples of in situ water harvesting include terracing, pitting and conservation tillage practices. These measures are also used for <span> </span>for soil conservation <span>(UNEP and SEI 2009)</span>.</span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Ex situ water harvesting is a technique where water is collected in an area external to where it falls and is stored for later use. Ex situ water harvesting is often used in urban areas natural soil surfaces or rooftops, roads and pavements in urban areas. Examples include capturing and storing water in dams, wells, ponds, cisterns, etc. (UNEP and SEI 2009). </span></p> <h4><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Benefits & Co-Benefits</span></h4> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">In situ water harvesting has multiple benefits. It allows for the collection of water in soil, thus increasing water infiltration and holding capacity which results in improved soil fertility for agriculture and/or biodiversity. Other benefits can include reduced runoff from slopes and facilitates groundwater recharge (Agriwaterpedia 2014).</span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Ex situ benefits are usually related to storing excess water, particularly stormwater runoff for productive use later. In urban areas, the reduced stormwater runoff volumes also contribute to minimizing the amount of pollutant loads entering stormwater collection systems, helping to prevent potentially damaging effects on water quality (EPA 2013). In addition, it contributes to water conservation, reducing the pressure on surface water sources and groundwater. When used for irrigation purposes in households, the harvested water also enhances groundwater recharge. In urban areas, reduced energy requirements for water treatment and transport can contribute to better air quality, and reduced CO2 emissions from local power plants. Even if treated for potable use, rainwater, in most cases, requires less energy than conventional water treatment and distribution.</span></p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Costs</span></h4> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Water harvesting measures vary in cost depending on type, design and scale. For example, in situ solutions in rural areas using traditional methods may be low cost and only incur the cost of labor and time. For ex situ methods, the building of storage tanks, cisterns, pumps, etc., will incur costs of its own. The scale is also a factor. </span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">The scale of water harvesting methods can also influence the hydrological regime of a river, particularly if its large-scale. For example, water harvesting that significantly reduces surface runoff may increase groundwater recharge and evaporation losses. This may negatively impact downstream water users, including ecosystems. When multiple users are involved and scale is significant, it is important to undertake comprehensive planning and with proper knowledge of the hydrological system in question.</span></p></div> <div class="clearfix text-formatted field field--name-field-literature-sources field--type-text-long field--label-above"> <div class="field__label">Literature sources</div> <div class="field__item"><h6>Agriwaterpedia (2014). Available from http://agriwaterpedia.info/wiki/Water_harvesting.</h6> <h6>UNEP and SEI (2010). AdaptCost Briefing Paper 3: Coastal Adaptation – Africa Review and New Estimates.</h6> <h6>EPA (2013). United States Environmental Protection Agency, Rainwater Harvesting: Conservation, Credit, Codes, and Cost. Literature Review and Case Studies.</h6></div> </div> <div class="field field--name-field-measure-category field--type-entity-reference field--label-above"> <div class="field__label">Measure category</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/76" hreflang="en">Mitigation</a></div> </div> </div> Fri, 02 Dec 2016 11:05:01 +0000 nst 188 at https://coastal-management.eu Sustainable Urban Drainage Systems (SUDS) https://coastal-management.eu/measure/sustainable-urban-drainage-systems-suds <span class="field field--name-title field--type-string field--label-hidden">Sustainable Urban Drainage Systems (SUDS)</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="https://coastal-management.eu/user/27" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">giacomo.cazzola</span></span> <span class="field field--name-created field--type-created field--label-hidden">Tue, 09/13/2016 - 12:57</span> <div class="field field--name-field-adressed-disks field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/54" hreflang="en">Urban floods</a></div> </div> <div class="field field--name-field-type-of-measure field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/61" hreflang="en">Surface Water Management</a></div> </div> <div class="field field--name-field-colour field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/66" hreflang="en">Combined approach (grey + green)</a></div> </div> <div class="clearfix text-formatted field field--name-field-short-descr field--type-text-long field--label-hidden field__item"><p>Approaches to manage surface water that take account of water quantity (flooding), water quality (pollution) biodiversity (wildlife and plants) and amenity are collectively referred to as Sustainable Urban Drainage Systems (SUDS). Such drainage systems not only help in preventing floods, but also improve water quality. In addition they can enhance the physical environment and wildlife habitats in urban areas.</p></div> <div class="clearfix text-formatted field field--name-field-information-source field--type-text-long field--label-hidden field__item"><p><em>Based on: <a href="https://openknowledge.worldbank.org/handle/10986/2241">Jha, Abhas K., Robin Bloch, and Jessica Lamond. Cities and Flooding: A Guide to Integrated Urban Flood Risk Management for the 21st Century. World Bank Publications, 2012.</a></em></p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p>A key characteristic of many artificial urban drainage systems, as compared with natural systems, is a more rapid build-up of flows and higher peaks, causing an increase in flood risk. It is possible to return the catchment response to a more natural state by using more natural methods of drainage. These use the infiltration and storage properties of semi-natural devices such as infiltration trenches and swales (both discussed below) or ponds, all of which slow down the catchment response, reducing the peak outflow and thus lowering the flood risk.</p> <p>SUDS devices are most effective in combination, in the form of a ‘management train’. Wherever possible, stormwater should be managed in small, cost-effective landscape features located within small sub-catchments, rather than being conveyed to and managed in large systems at the bottom of drainage areas. Water should be conveyed elsewhere only if it cannot be dealt with locally.</p> <p>Like all drainage systems, SUDS are designed to provide capacity for a storm event of a particular frequency. For more extreme events, exceedance flows are likely to be generated and must be carried by the major drainage system.</p> <p>Many SUDS devices are based on infiltration to the ground, the risk of groundwater pollution is an important consideration, especially where surface runoff is likely to be polluted and the groundwater is used for drinking supplies. The design of a permeable pavement system, for example, can be adjusted to allow infiltration, or not, in order to account for this (discussed below).</p> <p>The main types of SUDS devices, all of which are discussed later in this chapter, can be listed as:</p> <ul> <li>Inlet control</li> <li>Infiltration devices</li> <li>Vegetated surfaces</li> <li>Permeable paving</li> <li>Filter drains</li> <li>Infiltration basins</li> <li>Detention ponds</li> <li>Retention ponds</li> <li>Constructed wetlands.</li> </ul> <p>Inlet control devices provide storage close to the point where the rainfall is first collected. Rooftop ponding uses the storage potential of flat roofs; as this creates an additional load there is an increased need for water tightness, as well as good maintenance of outlet control devices. A green roof is a planted area that provides storage, encourages evapo-transpiration and improves water quality. A water store, consisting of a water butt or a tank near to ground level, can store rainwater and make it available for garden use, though some outflow must be assured to provide capacity for subsequent rainfall.</p> <p>Instead of connection to the drainage system, water collected from roofs can be diverted at the bottom of the downpipe to infiltrate in nearby stable pervious areas. Paved area ponding, to accommodate heavy rainfall, can be achieved by restricting inflow to the piped drainage system, thereby reducing flood risk downstream.</p> <p>Detention basins are storage facilities formed from the landscape with controlled outflow. They store stormwater temporarily, and are dry between storms.</p> <p>Retention ponds provide storage within a permanent body of water. They allow natural treatment of the water and provide environmental and amenity benefits.</p> <p>The benefits of SUDS can be realized in existing urban areas by retrofitting. Its challenges tend to be associated with availability of space, and the difficulty of adapting existing systems. Local application of inlet control may be the most feasible approach.</p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h3>Infiltration and permeability of urban areas</h3> <p>Urbanization affects the natural water cycle. When rain falls, some water returns to the atmosphere (through evaporation or transpiration by plants); some infiltrates the surface and becomes groundwater; and some runs off the surface. Since urbanization increases the proportion of the surface that is impermeable, it results in more surface runoff and reduced infiltration. As we have seen, surface runoff finds its way to a watercourse far quicker than groundwater and therefore increases flood risk, and if the surface runoff is conveyed via a piped drainage system the effect is even more pronounced.</p> <p>Increasing infiltration via improved permeability in urban areas can reduce flood risk, but in many cities the opposite is occurring. The increasing densification of towns and cities implies that every space is utilized to the maximum for the use of urban dwellers. This leads to an increase in hard surfaces and a decrease in permeability of any open space left after the construction of buildings. An example of this is the paving of front gardens in the UK to allow for parking spaces: in one part of London, 68 percent of the area of front gardens is now hard-surfaced, and the figure is rising. Leisure and recreational uses also tend to involve impermeable surfaces. Cost-cutting measures designed to limit the regular maintenance of green spaces can also lead to the concreting or de-greening of spaces.</p> <p>A major characteristic of most SUDS systems (as discussed above) is to increase permeability and therefore infiltration. The use of SUDS is promoted in the UK via formal Building Regulations, which state that ‘surface water drainage should discharge to a soakaway or other infiltration system where practicable’. Planning guidance in England, specifically related to development and flood risk, also strongly favors the use of SUDS in new developments. Measures like these have the effect of in-creasing infiltration, and are steps in the right direction in terms of preventing flood risk from increasing as a result of urbanization.</p> <h3>Infiltration devices</h3> <p>These include soakaways and infiltration trenches. A soakaway is an underground structure, typically circular in plan, which facilitates infiltration into the ground. An infiltration trench is a linear excavation, usually stone-filled, achieving the same aim with a greater area of exposure to the ground. These devices are only suitable in ground with suitable infiltration properties, positioned above the level of the water table at any time of year. Filter drains are perforated or porous pipes laid in a trench containing granular fill and are typically located in the verge of a road to collect water from the road surface and carry it away. Infiltration basins are open depressions in the ground which collect water and allow it to be absorbed gradually.</p> <h3>Vegetated surfaces</h3> <p>Swales are grass-lined channels which allow the infiltration, storage and conveyance of stormwater. Small swales can run beside local roads, large swales beside major roads, and swales may also form landscaped channels for conveyance of stormwater. Filter strips are gently sloping areas of vegetat-ed land. Swales and filter strips delay and reduce stormwater peaks, and trap pollutants and silts.</p> <h3>Permeable paving</h3> <p>Permeable paving creates a surface that allows infiltration, either because it is porous, or because specific openings have been provided (for example, the spaces between paving blocks). The most common applications are for car parks, but lightly trafficked roads and driveways are also suitable. The sub-base provides storage for rainwater, typically in the voids between granular particles. The collected water may then be allowed to infiltrate into the ground; alternatively, where it is important to protect groundwater from pollution, the base and sides may be sealed, and water flows to a piped outlet, but far more slowly than it would in a piped system.</p> <p>The only serious restriction on infiltration in urban areas is where there may be a risk of polluting groundwater that is used as a water resource.</p> <p>A significant solution to the problem of increased and more rapid rainfall runoff is by using the system of development permitting. Guidelines need to be issued giving examples of how urban design can maximize infiltration into groundwater. Permits are then only authorized if such appropriate measures are included in the construction works. On a wider level, urban area administrations need to draw up a land use management and zoning plan, which recognizes the need for open spaces that can act as temporary rainfall storage, as well as being an urban recreational amenity.</p> <p>Some agricultural practices reduce infiltration, and these increase flood risk to urban areas down-stream. Adapted agricultural practice to reverse these effects includes conservation tillage, ploughless cultivation and avoiding bare soil. The preservation and extension of existing wetlands and forests in the upstream areas of a catchment enhances infiltration, and in addition reduces runoff through evapo-transpiration. Primary forests with broad-leafed trees are much more effective in reducing runoff than planted pine species.</p></div> <div class="field field--name-field-relevant-case-studies-and- field--type-entity-reference field--label-above"> <div class="field__label">Relevant case studies and examples</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/measure/example-ekostaden-augustenborg-initiative-malmo-swe" hreflang="en">EXAMPLE: The Ekostaden Augustenborg initiative, Malmö (SWE)</a></div> </div> </div> <div class="field field--name-field-further-readings field--type-link field--label-above"> <div class="field__label">Further Readings</div> <div class="field__items"> <div class="field__item"><a href="http://ec.europa.eu/environment/integration/green_semester/pdf/Recreate_PB_2015_NBS_final_druck10-02-2016.pdf">Davis M et al. (2016) Coastal Protection and SuDS – Nature-Based Solutions (rec…</a></div> <div class="field__item"><a href="http://www.susdrain.org/">The UK based community for sustainable drainage</a></div> </div> </div> <div class="clearfix text-formatted field field--name-field-literature-sources field--type-text-long field--label-above"> <div class="field__label">Literature sources</div> <div class="field__item"><h5>Reed, B. 2004. Sustainable urban drainage in low-income communities – a scoping study. Loughborough: WEDC. http://www.dfi d.gov.uk/r4d/PDF/Outputs/R81681.pdf.</h5> <h5> </h5></div> </div> <div class="field field--name-field-measure-category field--type-entity-reference field--label-above"> <div class="field__label">Measure category</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/76" hreflang="en">Mitigation</a></div> </div> </div> Tue, 13 Sep 2016 10:57:04 +0000 giacomo.cazzola 100 at https://coastal-management.eu Land and soil management practices https://coastal-management.eu/measure/land-and-soil-management-practices <span class="field field--name-title field--type-string field--label-hidden">Land and soil management practices</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="https://coastal-management.eu/user/27" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">giacomo.cazzola</span></span> <span class="field field--name-created field--type-created field--label-hidden">Sun, 09/11/2016 - 23:47</span> <div class="field field--name-field-adressed-disks field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/53" hreflang="en">Riverine or slow rise floods</a></div> </div> <div class="field field--name-field-type-of-measure field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/61" hreflang="en">Surface Water Management</a></div> </div> <div class="field field--name-field-colour field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/66" hreflang="en">Combined approach (grey + green)</a></div> </div> <div class="clearfix text-formatted field field--name-field-short-descr field--type-text-long field--label-hidden field__item"><p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Soils face various risks related to erosion and pollution, however, adopting good land and soil management practices can help mitigate these negative impacts and in some cases can improve the overall productivity of soils. Such practices generally seek to improve soil structure and/or increase cover so as to reduce erosion, increase soil infiltration, and reduce runoff and transport of sediments. </span></p></div> <div class="clearfix text-formatted field field--name-field-information-source field--type-text-long field--label-hidden field__item"><p><a href="https://www.sepa.org.uk/media/163560/sepa-natural-flood-management-handbook1.pdf">Based on kindly provided information by SEPA's Natural Flood Management Handbook (p. 20f.)</a></p> <ul> </ul></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">According to Forbes et al. (2015), </span><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">s variety of techniques may be adopted including:</span></p> <ul> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">cover crops;</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">checking for and relieving compaction where required;</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">soil aeration;</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">machinery practices that minimise compaction; and</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">runoff control features (e.g. in-field buffer strips, hedges).</span></li> </ul> <h4><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Soil and crop management measures</span></h4> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Covering land with cover-crops during winter can help reduce soil erosion and maintain soil structure and fertility. Applying cover crops also reduces surface run off, the leaching of nutrients, weed control and also provides habitats for other species. Applying cover crops are particularly useful in areas that are drier and have more stable soils. Cultivating land along contours, rather than straight up and down field slopes can be particularly effective in reducing surface runoff. </span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Another measure is reducing the use or impact of machinery on soil compaction. The implementation of tramline spacing, flexible tyres on machinery, and reduced weight loads can help prevent compaction and ensuing problems of excessive runoff, particularly on wet soils. Another way to improve soil aeration and reduce compaction is to use a soil aerator (mechanical spiking of the soil) in compacted grass field, in combination with other measures, such as tramlines which benefit growth and increase the amount of oxygen reaching roots.</span></p> <h4><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Runoff control features</span></h4> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Watercourses that overflow can cause run-off into fields. Creating vegetated land strips along the banks of watercourses can provide important protection from grazing animals while stabilizing banks and reducing the possibility of erosion. This natural barrier technique can reduce erosion and the amount of water and pollutants reaching the watercourse, while also improving biodiversity. There are several implementation options which vary from simple fencing that allows natural regeneration and protection from stock or it could include some additional elements such as planting of trees and other vegetation.</span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Sub-dividing arable fields through the planting of grass strips and hedgerows along the contour of a field or within a natural gully can be particularly effective at intercepting surface runoff and increasing infiltration of water into the soil profile. Other agricultural practices and interventions that can contribute to reductions in runoff, such as ditch/ drain blocking and wetland creation, are described in more detail in subsequent sections.</span></p></div> <div class="field field--name-field-download-factsheet field--type-file field--label-inline clearfix"> <div class="field__label">Download Factsheet</div> <div class="field__item"> <span class="file file--mime-application-pdf file--application-pdf"> <a href="https://coastal-management.eu/sites/default/files/2016-12/SEPA-NFMH-20-21.pdf" type="application/pdf; length=75733">SEPA-NFMH-20-21.pdf</a></span> </div> </div> <div class="clearfix text-formatted field field--name-field-literature-sources field--type-text-long field--label-above"> <div class="field__label">Literature sources</div> <div class="field__item"><h6>Heather Forbes, Kathryn Ball and Fiona McLay (2015): Natural Flood Management Handbook. Published by Scottish Environment Protection Agency (https://www.sepa.org.uk/media/163560/sepa-natural-flood-management-handbook1.pdf)</h6> <h6>PARROTT, A., BROOKS, W., HARMAR, O. and PYGOTT, K. (2009). Role of rural land use management in flood and coastal risk management. Journal of Flood Risk Management, 2, 4, 272-284.</h6></div> </div> <div class="field field--name-field-measure-category field--type-entity-reference field--label-above"> <div class="field__label">Measure category</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/76" hreflang="en">Mitigation</a></div> </div> </div> Sun, 11 Sep 2016 21:47:08 +0000 giacomo.cazzola 89 at https://coastal-management.eu Drainage system management https://coastal-management.eu/measure/drainage-system-management <span class="field field--name-title field--type-string field--label-hidden">Drainage system management</span> <span class="field field--name-uid field--type-entity-reference field--label-hidden"><span lang="" about="https://coastal-management.eu/user/27" typeof="schema:Person" property="schema:name" datatype="" xml:lang="">giacomo.cazzola</span></span> <span class="field field--name-created field--type-created field--label-hidden">Tue, 09/06/2016 - 16:39</span> <div class="field field--name-field-adressed-disks field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/54" hreflang="en">Urban floods</a></div> </div> <div class="field field--name-field-type-of-measure field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/57" hreflang="en">Reduction</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/61" hreflang="en">Surface Water Management</a></div> </div> <div class="field field--name-field-type-of-coastal-defence-st field--type-entity-reference field--label-hidden field__item"><a href="https://coastal-management.eu/taxonomy/term/73" hreflang="en">Limited intervention</a></div> <div class="field field--name-field-colour field--type-entity-reference field--label-hidden field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/67" hreflang="en">Grey infrastructure</a></div> </div> <div class="clearfix text-formatted field field--name-field-short-descr field--type-text-long field--label-hidden field__item"><p>Urban drainage systems need to be able to deal with both wastewater and stormwater whilst minimizing problems to human life and the environment, including flooding. Urbanization has a significant effect on the impact of drainage flows on the environment: for example, where rain falls on impermeable artificial surfaces and is drained by a system of pipes, it passes much more rapidly to the receiving water body than it would have done when the catchment was in a natural state. This causes a more rapid build-up of flows and higher peaks, increasing the risk of flooding (and pollution) in the receiving water. Many urban drainage systems simply move a local flooding problem to another location and may increase the problem. In many developed counties there is a move away from piped systems, towards more natural systems for draining stormwater.</p></div> <div class="clearfix text-formatted field field--name-field-information-source field--type-text-long field--label-hidden field__item"><p>Based on: <a href="https://openknowledge.worldbank.org/handle/10986/2241"><em>Jha, Abhas K., Robin Bloch, and Jessica Lamond. Cities and Flooding: A Guide to Integrated Urban Flood Risk Management for the 21st Century. World Bank Publications, 2012.</em></a></p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p>Where the drainage system of an urban area is piped, by a ‘sewer system’, there are two approaches in use: ‘combined’ or ‘separate’.</p> <p>The older parts of many cities (New York being an example) are drained using the combined system, whereby wastewater and stormwater are mixed and are carried together. The system takes the combined flow to the point of discharge into the natural water system, commonly via a wastewater treatment plant that discharges treated effluent. During heavy rainfall events, the stormwater flow will greatly dominate the wastewater flow in terms of volume, but it is hardly ever viable to provide sufficient capacity throughout the system for stormwater resulting from heavy rainfall, as the system would operate at a small fraction of its capacity during dry weather. Instead, structures are included in the system to permit overflow to a nearby watercourse. During significant rainfall events a significant volume of the flow is likely to overflow, rather than to continue to the wastewater treatment plant. As the overflowed water is generally a dilute mixture of wastewater and stormwater, these structures are designed hydraulically to prevent larger, visually offensive solids from being discharged to the river. However, the inescapable fact is that combined sewer overflows inevitably cause some pollution (Butler and Davies 2011).</p> <p>In the urban areas served by a combined system, capacity is similarly exceeded by extreme stormwater flows. Under these circumstances, the ‘surcharging’ of the system may cause flooding of the urban surface and, as the flood water will include wastewater, there are associated pollution and health implications.</p> <p>In a separate system, wastewater and stormwater are drained by separate pipes, often constructed in parallel. Wastewater is carried to the wastewater treatment plant, whereas stormwater is usually discharged direct to the nearest watercourse. The problem of combined sewer overflows is thereby avoided, but there are still challenges: stormwater discharge is usually untreated, and this may cause pollution. Stormwater may enter the wastewater pipe  either through mistaken or unauthorized connections; there may also be infiltration of groundwater at pipe imperfections. Because of the relative proportions of wastewater and stormwater during heavy rainfall, these additional inputs may significantly reduce the capacity of the pipe for the wastewater it was designed to carry.</p> <p>In urban areas without conventional piped sewer systems, disposal of excreta and wastewater is likely to be localized, though in some cases simplified (shallow and small diameter) pipes are used. Stormwater is most likely to be carried by open drains, typically unlined channels along the side of the street. Better constructed channels may be lined with stone or concrete, and may be integrated into the urban landscape. Open drains are far cheaper to construct than stormwater sewers, and although they can easily become blocked by debris or refuse from the surface, such blockages are more easily monitored and removed than in piped systems.</p> <p>Maintenance is vital, not only to remove obvious obstructions, but also cleaning out deposited sediment, and then disposing of the material so that it does not go back into the drain. In heavy rain, the capacity of an open urban drainage channel may quickly be exceeded; in a well planned system, overflow should be to a specified ‘<a href="http://coastal-management.eu/types-flood-storage">major system</a>’ such as a road which can act as a drainage channel.</p> <p>Where there is no adequate system for disposal of wastewater, there is a high likelihood that open drains will be contaminated by foul sewage. This could come from contributions from areas without sewers, or from discharge from simplified sewerage which does not lead to an adequate treatment facility. Open drains may also be misused for the disposal of domestic solid waste. Where the quality of stormwater carried in open drains is an issue for these reasons, there may be limited opportunities for using semi-natural systems of urban drainage that rely on the storage or infiltration of stormwater because of public health issues.</p></div> <div class="clearfix text-formatted field field--name-field-literature-sources field--type-text-long field--label-above"> <div class="field__label">Literature sources</div> <div class="field__item"><p>Butler D. and Davies J.W. 2011 Urban Drainage, 3rd edition. UK: Spon Press.</p></div> </div> <div class="field field--name-field-scale field--type-entity-reference field--label-above"> <div class="field__label">Scale</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/71" hreflang="en">Individual - private</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/70" hreflang="en">Local</a></div> </div> </div> <div class="field field--name-field-measure-category field--type-entity-reference field--label-above"> <div class="field__label">Measure category</div> <div class="field__items"> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/76" hreflang="en">Mitigation</a></div> </div> </div> Tue, 06 Sep 2016 14:39:06 +0000 giacomo.cazzola 63 at https://coastal-management.eu