Natural flood, runoff, catchment management https://coastal-management.eu/ en Reconnecting rivers to floodplains https://coastal-management.eu/measure/reconnecting-rivers-floodplains <span class="field field--name-title field--type-string field--label-hidden">Reconnecting rivers to floodplains</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">Mon, 02/20/2017 - 10:27</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/58" hreflang="en">Natural flood, runoff, catchment management</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/59" hreflang="en">Water flow regulation</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>River restoration contributes to flood risk management by supporting the natural capacity of rivers to retain water. As flood risk consists of damage times occurrence, flood risk <em>management </em>needs to reduce either the damage, or the likelihood of floods to occur, or both. River restoration reduces the likelihood of high water levels, and improves the natural functions of the river at same time.</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>In a natural river system a river spreads water beyond its banks and over extended areas of a floodplain during periods of high water. In order to protect property and contain waters, the classic flood risk management approach is to constrain watercourses with rivers being straightened and building dykes to increase discharge capacity, dredging to deepen channels, and building reservoirs and artificial retention areas to store excess waters.</p> <p>While this generally reduces the likelihood of flooding, in the event of extremely high waters it increases the amount of damage if the engineered system is overwhelmed or fails. Without natural features such as wetlands and meanders, excess waters cannot be absorbed. Any breach will release an enormous amount of water, with potentially catastrophic consequences. Continuously reinforcing and building higher dykes cannot overcome this weakness, and is a very expensive option. Historically, engineering solutions upstream have created peak flows downstream, leading to more engineering. Moreover, climate change scenarios predict more extreme weather events and higher sea levels. A new approach is needed.</p> <h4>Advantages</h4> <p>By re-connecting brooks, streams and rivers to floodplains, former meanders and other natural storage areas, and enhancing the quality and capacity of wetlands, river restoration increases natural storage capacity and reduces flood risk. Excess water is stored in a timely and natural manner in areas where values such as attractive landscape and biodiversity are improved and opportunities for recreation can be enhanced. In these ways, river restoration directly contributes to climate change strategies aimed at mitigating the effects of increased and erratic peak flows and droughts.</p> <p>River restoration is increasingly being delivered by flood risk managers to create space for flood water. Reconnecting floodplains to the river and managed realignment in estuaries is an important mechanism of water management.</p> <p>Future climate change will potentially affect all aspects of the rainfall regime. The precise nature of these changes is uncertain, particularly for those extreme events, whether of short or long-duration, which tend to lead to flooding. Increases in rainfall at all scales will increase the risk of flooding to a greater or lesser extent, depending on how these increases manifest themselves in space and time and of the rainfall-runoff characteristics of the catchment in question.</p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Benefits</h4> <p>River restoration improves flood protection, but it also brings about co-benefits that are multifold. Firstly, river restoration can improve flood storage capacity of a river and reduce the volume and speed of water. Some of the co-benefitst can include cost reductions by removing the need to maintain hard infrastructure and also improving the quality of water, and thus in turn drinking water costs. Improved biodiversity and the creation of natural wetlands is another adjunct result of river restoration using green infrastructure.  Finally it improves resilience to climate change by creating new floodplanes for increased water storage, green networks and more natural space for people and wildlife during higher temperatures.</p> <h4>Costs</h4> <p>There are different kinds and degrees of river restoration. A larger scale project can include an entire floodplane, removing past structures and restoring natural processes and channels of a water course. A smaller project may simply be removing structures in one place, and replacing them with more natural features.</p> <h4>Barriers to Implementation</h4> <p>Lack of funding is often cited as a key reason for failing to restore watercourses and rivers, as well as, consensus in agreement of users of a river. Given that restoration can take place on either a large or small scale, the associated barriers often also relate to how extensive the project is.</p></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> Mon, 20 Feb 2017 09:27:15 +0000 nst 296 at https://coastal-management.eu EXAMPLE: Reconnecting lakes to the Yangtze River (CHN) https://coastal-management.eu/measure/example-reconnecting-lakes-yangtze-river-chn <span class="field field--name-title field--type-string field--label-hidden">EXAMPLE: Reconnecting lakes to the Yangtze River (CHN)</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 - 12:16</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/58" hreflang="en">Natural flood, runoff, catchment 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>The 6,300 km long Yangtze River in China was facing a reduction of wetlands areas and flood retention capacity. In 2002, the World Wide Fund for Nature (WWF) initiated a programme to reconnect lakes in Hubei<br /> Province to the Yangtze River through opening the sluice gates and facilitating sustainable lake<br /> management. These wetlands can store floodwaters and therefore reducing vulnerability to flooding in the central Yangtze region.</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"><h4>General description</h4> <p>The Yangtze River is 6,300 km long and home to more than 400 million people. The river basin drains a 1,800,000 km basin and has extensive lakes and floodplains of significant environmental and retention importance. In the summer, the basin experiences floods, especially in the central Yangtze. Extensive development in the last fifty years has converted 1,066 lakes 757 coverings along 2,150 km2 into polders, reducing wetland areas by 80% and flood retention capacity by 75%.</p> <p>Since 1991 there have been several highly damaging flood events that have killed thousands of people and cost billions of dollars. The Lakes and basin have also become extremely polluted, in particular because of the application of fertilizer to aquaculture pens. The loss of connection to the Yangtze River prevents diluting flows and the migration of fish. Drought in recent years has increased water pollution, and climate change and increased temperatures are expected to worsen eutrophication</p> <p>In 2002, the World Wide Fund for Nature (WWF) initiated a programme of sustainable lake management to reconnect the lakes in the Hubai Province to the Yangtze River through opening the sluice gates. The programme focused on three lakes: Zhangdu (40 km2), Hong (348 km2 and Tian’e Zhou (20 km2). Given the poverty of the populations in the region, finding alternative and sustainable livelihoods and sources of income was important. The average income of residents in the area was just USD 1.34 per day. WWF formed partnerships with government agencies and others to explore options for more sustainable river basin management.           </p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Ecosystem-based aspects</h4> <p>Since 2004-2005 in Hubei Province, the sluice gates at lakes Zhengdu, Hong and Tien’e Zhou have been seasonally re-opened and illegal and uneconomic aquaculture facilities and other infrastructure removed or modified. Now these 448 km2 wetlands can store up to 285 Mm3 of floodwaters, reducing vulnerability to flooding in the central Yangtze region.</p> <p>The forced ending or removal of illegal or unsustainable aquaculture have reduced pollution levels. In Lake Hong, pollution fell from national pollution level IV (fit for agricultural use only) to II (drinkable) on China’s five-point scale.</p> <p>Of immediate benefit for the Yangtze River Basin was the increase in wild fisheries species diversity and populations. Within six months of reconnection of Zhangdu Lake, the catch increased by 17 per cent and nine fish species returned to the lake. Similarly the catch increased by 15 per cent in Baidang Lake. Development of certified eco-fish farming by 412 households increased income of fishers by 20 to 30 per cent on average. Similarly, the income from fisheries at the Yangcai Hu area of Hong Lake increased by 25 per cent after restoration. Bamboo farming has also been implemented as a measure to stabilize steeper lands near the lakes. Twelve migratory fish species have now returned to the lakes. At Zhangdu Lake, 60 km2 of lake and marshland were designated as a nature reserve by the Wuhan Municipal Government. To strengthen the effectiveness of wetland conservation efforts in the Yangtze River basin, a Nature Reserve Network was established to link 17 nature reserves (12 later designated) covering 4,500 km2. As a result of these benefits, in 2006 the Hubei Provincial Government adopted a wetlands conservation master plan and allocated resources to protect 4,500 km2 by 2010.</p> <p>The success of these adaptations was replicated in other areas of the Yangtze and China.</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>Combined using a green and grey approach. The implementation of sluice gates allowed for seasonal opening and reconnection of regional lakes to the Yangtze River. Reconnecting the water flows required the removal of some aquaculture businesses, but brought up overall levels of fisheries in the river basin with significantly more migratory species returning to the area, which in turn boosted incomes of local fishers. The environmental effects also significantly improved water quality which was extremely polluted prior to the facilitation of water flow via connecting the lakes to the tributaries.</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/flood-storage-systems" hreflang="en">Flood storage systems</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> Thu, 16 Feb 2017 11:16:41 +0000 nst 294 at https://coastal-management.eu EXAMPLE: Restoring Riparian Forests (BG) https://coastal-management.eu/measure/example-restoring-riparian-forests-bg <span class="field field--name-title field--type-string field--label-hidden">EXAMPLE: Restoring Riparian Forests (BG)</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, 01/27/2017 - 11:08</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/58" hreflang="en">Natural flood, runoff, catchment 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>Floodplain or riparian forests can be extremely important for the prevention of floods and landslides. Floodplain forests used to be widespread in Bulgaria, but today they are only partially preserved. WWF, in partnership with local Bulgarian partners began a project for restoration and conservation of natural riparian forests of native species along the rivers Danube and Maritsa.</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 the project description of the <a href="http://www.wwf.bg/what_we_do/forests/riparian_forests/about_the_project/">WWF </a>and <a href="http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=search.dspPage&n_proj_id=5083">LIFE+</a></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>Riparian forests are rich in biodiversity, naturally purifying water, and can prevent floods and landslides. During heavy rain falls, riparian forests collect the water and then slowly return some in the riverbeds, therefore slowing down the water flow. Riparian forests create unique conditions that control and influence the transfer of energy, nutrients and sediments between the aquatic and terrestrial ecosystems.</p> <p>These riparian forests have experienced frequent disturbance by human impact, resulting in a continuous decrease of the habitat area. In recent decades, they have suffered from a wide range of detrimental actions including: clear fellings; transformation into arable lands or hybrid plantations for intensive production of timber; cleaning/correction of riverbeds; and infrastructure projects or activities (such as the construction of small hydropower plants and the extraction of inert materials). Such long-term adverse human impacts lead to degradation of the priority habitat and negative changes in its structure, composition, stability and functionality.</p> <p>The WWF together with local Bulgarian partners (National Forestry and regional forestry directorates "Ruse" and "Plovdiv") have applied for a LIFE+ project to restore 48.1 hectares of natural riparian forests. They will plant local tree species and remove exotic species. A guide will be developed for the recovery and management of riparian forests as well as an analysis of the relationship between the targeted areas and the other Natura 2000 sites. Additionally, volunteers will actively be engage in the project and in particular highschool students, who will help with the planting of trees.</p> <p>The project is co-funded by the LIFE + instrument of the European Commission and will be implemented from September 2014 to 2019 with a total budget of around 500.000€.</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>Restoring riparian forests can not only mitigate flooding problems to a certain extent, it also provides additional ecosystem services. While this concept could be difficult to implement in coastal urban areas due to the lack of space, it can be a valuable approach in rural areas. But also in rural the aspect of sufficient space is probably the most crucial factor in implementing the measure. If this initial obstacle is solved, the reforestation is a promising ecosystem-based approach.</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/reafforestation-upland-areas-and-buffer-zones" hreflang="en">Reafforestation in upland areas and buffer zones</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.wwf.bg/what_we_do/forests/riparian_forests/about_the_project/">WWF project description</a></div> <div class="field__item"><a href="http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=search.dspPage&n_proj_id=5083">LIFE+ project description</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> Fri, 27 Jan 2017 10:08:18 +0000 nst 285 at https://coastal-management.eu Marsh vegetation in intertidal and coastal zone https://coastal-management.eu/measure/marsh-vegetation-intertidal-and-coastal-zone <span class="field field--name-title field--type-string field--label-hidden">Marsh vegetation in intertidal and coastal zone</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 - 21:51</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/35" hreflang="en">Estuarine floods</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/37" hreflang="en">Coastal floods or storm surges</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/36" hreflang="en">Erosion</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/58" hreflang="en">Natural flood, runoff, catchment 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/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><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Saltmarsh and mudflats are usually located together with mudflats in front of the saltmarsh. Saltmarsh vegetation and saltmarsh creeks help manage floods by dissipating wave and tidal energy.  They are valuable barriers to the risks of flood, as they dissapte wave and tidal energy. Saltmarshes used in combination with other measures can have beneficial outcomes to managing climate change impacts. Even a small width of fronting saltmarsh can significantly reduce the height of sea walls required to achieve the same level of protection and thus also reduce initial construction costs. Having saltmarsh fronting will also significantly reduce maintenance costs due to the reduced exposure to wave and tidal energy.</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. 52ff.)</a></p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><h4><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Where is restoration of saltmarsh appropriate?</span></h4> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Saltmarsh and mudflats are unique habitates comprised of fine grain sediments (silts and clays) that settle out of the water colomn in calm areas or where there is low water speed. Saltmarsh is usually found in estuaries or sheltered areas such as bays or at the head of sea lochs. The overall shape of the estuary or bay determines the location and extent of saltmarsh and mudflat. Development of mature saltmarsh typically takes between 40 to 80 years. However, this will not be possible in all locations, particularly where existing protection structures restrict the establishment of higher zones.</span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Determining whether conditions are good for the development of saltmarsh is difficult. In addition to naturally occurring physical processes, the nutrients determine if conditions are favourable for the establishment of saltmarsh and chemical pollutants can affect whether saltmarsh can colonise mudflat. Therefore, it is generally better to increase the extent or facilitate the relative stability of existing saltmarsh, rather than attempt to establish this habitat in new areas where it has not been present historically.</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">Restoring saltmarsh</span></h4> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">The size of the saltmarsh habitat is often determined by the tidal range. To increase the size or space for a saltmarsh habitat, it can be extended seawards or re-aligned by moving existing coastal structures inland. </span></p> <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">sediment can be placed at various levels in the morphological profile:</span></p> <ul> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">a thin layer of sediment can be sprayed over existing habitat to increase existing intertidal elevation; or</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">sediment can be placed in the intertidal zone to artificially increase the intertidal area; or</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">sediment can be placed in the sub-tidal zone to reduce erosion from intertidal margins</span></li> </ul> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">To encourage sediment to settle and saltmarsh to establish the following techniques can be used:</span></p> <ul> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Brushwood fascines/groynes: Small wooden posts erected in parallel rows and in-filled with brushwood to create a small fence. Other materials can be used but brushwood has been found to be the most durable. The best orientation is generally at right angles to the foreshore.</span></li> <li><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Polders: Brushwood fences or fascines are erected that enclose a width of mature marsh with a similar sized seaward extent of mudflat. Ditches are dug to collect deposited sediment, which is then piled onto banks between the ditches.</span></li> </ul> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">Saltmarsh can be left to naturally colonise the mudflats. However, unless there are good natural sources of local seeds, planting or sowing will be needed. Planting has generally been shown to be more effective than sowing. </span></p> <p><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">The majority of the costs associated with establishing saltmarsh will be the associated costs of re-charge or managed realignment required. If polders are used, the costs of establishing and maintaining these can also be significant. </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-52-54.pdf" type="application/pdf; length=167227">SEPA-NFMH-52-54.pdf</a></span> </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/example-wallasea-island-wild-coast-project-uk" hreflang="en">EXAMPLE: Wallasea Island Wild Coast project (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"><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></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 19:51:14 +0000 giacomo.cazzola 87 at https://coastal-management.eu Riparian buffers https://coastal-management.eu/measure/riparian-buffers <span class="field field--name-title field--type-string field--label-hidden">Riparian buffers</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 - 21:40</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/36" hreflang="en">Erosion</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/58" hreflang="en">Natural flood, runoff, catchment 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/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>Riparian buffers are vegetated, often forested, areas (“strips”) adjacent to streams, rivers, lakes and other waterways protecting aquatic environments from the impacts of surrounding land use (Enanga et al. 2010). Use of riparian buffers to maintain water quality in streams and rivers is considered to be a best forest and conservation management practice in many countries and is mandatory in some areas.</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"><h4>Benefits</h4> <p>Riparian buffers help to maintain water quality in waterways by protecting streams from non-point source pollution (e.g. from surrounding agricultural activities). Riparian vegetation cover prevents sediments, as well as such pollutants as nitrogen, phosphorus and others from entering water through biological (e.g. nutrient uptake by riparian vegetation) and physical-chemical (e.g. nutrient absorption for phosphorus which binds to clay particles and sediments) processes (Enanga et al. 2010).</p> <p>Vegetation and tree roots also stabilize banks and prevent erosion. During flood events, riparian vegetation slows down runoff by absorbing excess water, reduces peak flow and helps to mitigate potential flood damage downstream (Colgan et al. 2013). Such buffer strips also yield benefits in agricultural areas, both by retaining sediment and nutrients from entering the waterways, thereby preventing water pollution, and maintaining soil productivity on the fields (Schmidt and Batker 2012). Some studies show that riparian buffers can help to reduce the amount of sediment reaching the streams by as much as 80 per cent (Crétaz and Barten 2007).</p> <p>Trees also provide shade and reduce water temperature fluctuations, which is an important factor for the survival of many aquatic species. Shade provided by riparian vegetation also contributes to maintaining water quality, as high levels of light leads to increases in in-stream primary production, and can change the invertebrate species composition (Parkyn 2004). Increases in summer water temperatures can increase anoxia in stratified lakes, elevate the rate of phosphorus releases from lake and slow moving river sediments and cause algal blooms (Whitehead et al. 2009). Together with changes in actual water flows that affect riparian vegetation and water biota, the combined factors can impact on riparian food webs (Covich et al. 1999). A recent study in Denmark found that relatively short stretches (100–500 m) of riparian forest combat the negative effects of heating of stream water (Kristensen et al. 2013).</p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Co-benefits</h4> <p>Depending on the extent and the type of vegetation in the riparian buffers, they can provide important biodiversity benefits. Vegetation provides biodiversity habitat for many species, that in some cases can be particularly beneficial for agricultural activities via insects and birds that facilitate pollination of the fields. The cover and shade also provide favourable conditions for birds and other animals that can take refuge in the buffer zones, and which use the riparian buffer zones as corridors for movement. This is important for pastoralist communities that often rest animals in riparian areas for watering, grazing and protection. Riparian vegetation, either designed or natural, is sometimes referred to as “shelterbelts” and offer shade and weather protection (due to cooling effects). They also reduce wind velocities, dust (including air pollutants) and erosion (Bird et al. 1992; Bird 1998; Heath et al. 1999).</p> <p>In addition, riparian buffers can offer aesthetic and recreation value to nearby communities (Schmidt and Batker 2012). Drought, however, can weaken the resilience of intact riparian vegetation and larger forest ecosystems to pests and disease (Anderson 2008). The falling leaves and debris in turn provide food for aquatic species (Parkyn 2004). Moreover, water systems containing too many dead leaves and stored organic matter can become hypoxic, with decreased pH and fairly high concentrations of tannin and lignin, making the water toxic to fish and other aquatic species (Gehrke et al. 1993; Bond et al. 2008).</p> <h4>Costs</h4> <p>Costs associated with establishment and conservation of riparian buffer strips include land acquisition and any associated foregone economic opportunity, and when necessary, the planting of buffer zones. Where riparian land is on private property, public investment may need to be made for land acquisition or economic incentives for private landowners to establish riparian buffers.</p></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://climate-adapt.eea.europa.eu/metadata/adaptation-options/establishment-and-restoration-of-riparian-buffer-s">Climat Adapt on riparian buffer</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>Alexander, S. and McInnes, R. (2012). The benefits of wetland restoration. Ramsar Scientific and Technical Briefing Note No. 4. Ramsar Convention Secretariat, Gland, Switzerland.</h5> <h5>Anderson, J. ed. (2008). Climate change-induced water stress and its impact on natural and managed ecosystems. Study for the European Parliament’s Temporary Committee on Climate Change. Available from http://www.europarl.europa.eu/activities/committees/studies/download.do?file=19073.</h5> <h5>Bird, P.R. (1998). Tree windbreaks and shelter benefits to pastures in temperate grazing systems, Agroforestry Systems, vol. 41, 35-54.</h5> <h5>Bird, P.R., Bicknell, D., Bulman, P.A., Burke, S.J.A., Leys, J.F., Parker, J.N., van der Sommen, F.J. and Voller, P. (1992). The role of shelter in Australia for protecting soils, plants and livestock, Agroforestry Systems, vol. 18, pp. 59-86.</h5> <h5>Bond, N. R., Lake, P. S. and Arthington, A. H. (2008). The impacts of drought on freshwater ecosystems: an Australian perspective.  Hydrobiologia, vol. 600, pp. 3-16.</h5> <h5>Colgan, C.S., Yakovleff, D. and Merrill, S.B. (2013). An Assessment of the Economics of Natural and Built Infrastructure for Water Resources in Maine. (May).</h5> <h5>Covich, A.P., Palmer, M.A. and Crowl, T.A. (1999). The role of benthic invertebrate species in freshwater ecosystem, BioScience, vol. 49, pp. 119-127.</h5> <h5>De la Crétaz, A. and Barten, P. K. (2007). Land Use Effects on Streamflow and Water Quality in the Northeastern United States. CRC Press.</h5> <h5>Echavarria, M. (2002). Financing Watershed Conservation: The FONAG Water fund in Quito, Ecuador. In Selling Forest Environmental Services: Market-based Mechanisms for Conservation and Development, Pagiola, S., Bishop, J. and Landell-Mills, N., eds. London: Earthscan Publications.</h5> <h5>Enanga E.M., Shivoga W.A., Maina-Gichaba C., Creed I.F. (2010). Observing Changes in Riparian Buffer Strip Soil Properties Related to Land Use Activities in the River Njoro Watershed, Kenya, Water Air Soil Pollution, vol. 218, pp. 587–601.</h5> <h5>EPA (2012). United States Environmental Protection Agency, River Corridor and Wetland Restoration. Available from http://water.epa.gov/type/wetlands/restore/index.cfm.</h5> <h5>Forslund, A. et al. (2009). Securing Water for Ecosystems and Human Well-being: The Importance of Environmental Flows. Swedish Water House Report 24. SIWI. Available from http://www.unepdhi.org/~/media/Microsite_UNEPDHI/Publications/documents/unep_DHI/Environmental%20Flows%20Report%2024%20-low-res.ashx.</h5> <h5>Gehrke, P.C., Revell, M.B. and Philbey, A.W. (1993). Effects of river red gum, Eucalyptus camaldulensis, litter on golden perch, Macquaria ambigua, Journal of Fish Biology, vol. 43, pp. 265–279.</h5> <h5>Harding, J. S.,Claassen, K. and Evers, N. (2006). Can forest fragments reset physical and waterquality conditions in agricultural catchments and act as refugia for forest stream invertebrates?, Hydrobiologia, vol. 568, pp. 391-402.</h5> <h5>Heath, B.A., Maughan, J.A., Morrison, A.A., Eastwood, I.W., Drew, I.B. and Lofkin, M. (1999). The influence of wooded shelterbelts on the deposition of copper, lead and zinc at Shakerley Mere, Cheshire, England. The Science of the Total environment, vol. 235, No. 1-3, pp. 415-417. (September).</h5> <h5>Nilsson, C. and Renöfält, B.M. (2008). Linking flow regime and water quality in rivers: a challenge to adaptive catchment management, Ecology and Society, vol. 13, No. 2, p. 18.</h5> <h5>Russi, D., ten Brink, P., Farmer, A., Badura, T., Coates, D., Förster, J., Kumar, R. and Davidson, N. (2013). The Economics of Ecosystems and Biodiversity for Water and Wetlands. IEEP, London and Brussels; Ramsar Secretariat, Gland, Switzerland.</h5> <h5>Silva, J. P., Toland, J., Jones, W., Eldridge, J., Hudson, T., O’Hara, E. and Thévignot, C. (2010). LIFE building up Europe’s green infrastructure. Addressing connectivity and enhancing ecosystem functions, European Union.</h5> <h5>Schmidt, R. and Batker, D. (2012). Nature’s Value in the McKenzie Watershed: A Rapid Ecosystem Service Valuation, Earth Economics. (May).</h5> <h5>Parkyn S. (2004). Review of Riparian Buffer Zone Effectiveness, MAF Technical Paper No: 2004/05. (September).</h5> <h5>Whitehead, P.G., Wilby, R.L., Batterbee, R.W., Kernan, M. and Wade, A.J. (2009). A review of the potential impacts of climate change on surface water quality. Hydrological Sciences, vol. 54, No. 1, pp. 101-123.</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> Sun, 11 Sep 2016 19:40:18 +0000 giacomo.cazzola 86 at https://coastal-management.eu Wetland restoration https://coastal-management.eu/measure/wetland-restoration <span class="field field--name-title field--type-string field--label-hidden">Wetland restoration</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 - 21:25</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/37" hreflang="en">Coastal floods or storm surges</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/36" hreflang="en">Erosion</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/58" hreflang="en">Natural flood, runoff, catchment 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/32" hreflang="en">Hold the line</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/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>Wetland restoration can serve to reduce coastal flooding and erosion. It has also additional benefits like provide new habitats or improve the landscape for recreational purposes. Wetland restoration relates to the rehabilitation of previously existing wetland functions from a more impaired to a less impaired or unimpaired state of overall function.</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 kindly provided information by the<a href="http://www.climatetechwiki.org/content/wetland-restoration"> ClimateTechWiki</a> and the TNA Guidebook on '<a href="http://www.unep.org/pdf/TNAhandbook_CoastalErosionFlooding.pdf">Technologies for Climate Change Adaptation'</a> by Matthew M. Linham & Robert J. Nicholls</p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p>Although similar to managed realignment, wetland restoration can be distinguished by the goal to maintain the present position of the coastline as opposed to realigning landward, as occurs under managed realignment.</p> <p>The most commonly restored wetland ecosystems for coastal protection are saltmarshes and mangroves. Seagrasses may also be employed as a coastal defence, to dampen waves but on their own they are seldom considered an adequate shore protection alternative (USACE, 1989).</p> <p>Wetland habitats are important because they perform essential functions in terms of coastal flood and erosion management. They induce wave and tidal energy dissipation (Brampton, 1992) and act as a sediment trap for materials, thus helping to build land seawards. The dense root mats of wetland plants also help to stabilise shore sediments, thus reducing erosion (USACE, 1989).  Wetland restoration re-establishes these advantageous functions for the benefits of coastal flood and erosion protection. </p> <h4>Advantages of the technology</h4> <p>In terms of climate change adaptation in the coastal zone, the main benefit of wetland restoration is the reduction of incoming wave and tidal energy by enhancing energy dissipation in the intertidal zone.  This is achieved by increasing the roughness of the surface over which incoming waves and tides travel (Nicholls et al., 2007).  This reduces the erosive power of waves and helps to reduce coastal flood risk by diminishing the height of storm surges. </p> <p>A reduction in installation and maintenance costs of sea defences may occur when such structures are located behind large areas of saltmarsh.  In contrast to hard defences, wetlands are capable of undergoing ‘autonomous’ adaptation to SLR, through increased accumulation of sediments to allow the elevation of the wetland to keep pace with changes in sea level (Nicholls & Klein, 2005).  Provided wetlands are not subjected to coastal squeeze, and the rate of SLR is not too rapid to keep pace, wetlands are capable of adapting to SLR without further investments. </p> <p>Coastal wetlands also provide a number of important ecosystem services including water quality and climate regulation, they are valuable accumulation sites for sediment, contaminants, carbon and nutrients and they also provide vital breeding and nursery ground for a variety of birds, fish, shellfish and mammals. They are also a sustainable source of timber, fuel and fibre (White et al., 2010). </p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Disadvantages of the technology</h4> <p>The disadvantages of wetland restoration are minimal.  One possible disadvantage is the space requirement in locations which are often of high development potential.  This must be carefully weighed against the range of benefits accrued. </p> <h4>Financial requirements and costs </h4> <p>Because the term ‘wetland’ refers to a diverse range of habitats, it is difficult to give accurate cost estimates.  Different types of wetland will require different restorative measures with varying costs and labour requirements. The cost of individual projects should be calculated on a case-by-case basis. A number of factors which are likely to contribute toward variations in costs are given below (Tri et al. 1998):</p> <ul> <li>Type of wetland to be restored, expertise availability, and consequent chances of success</li> <li>Degree of wetland degradation and consequent restoration requirements</li> <li>Intended degree of restoration (for example, it may not be possible to restore all the ecosystem functions of a wetland if it is located in a highly industrialised/urbanised environment and the planned restoration measures may be less ambitious)</li> <li>Land costs if land purchase is required to convert to wetlands</li> <li>Labour costs</li> <li>Transportation distance between seedling source and planting site</li> <li>Seedling mortality rate between collection and planting</li> <li>Cost of raising specific species in nurseries before transplantation because they cannot be directly planted on mud flats due to strong wind and wave forces</li> <li>Scale of post-implementation monitoring operations</li> </ul> <h4>Institutional and organisational requirements</h4> <p>At a local level, proactive measures can be implemented to ensure wetland habitats are maintained and used in a sustainable manner.  This will preserve habitats into the future and reduce or even avoid the cost of restoration and planting schemes.  By preventing wetland loss or degradation, it is also possible to avoid the many potential problems encountered in the course of wetland restoration efforts (NRC, 1992).</p> <p>At a larger scale, it is useful for governments to adopt proactive coastal management plans to protect, enhance, restore and create marine habitats.  Without such a framework, action to restore wetlands is likely to be fragmented and uncoordinated (NRC, 1994).  This is compounded by the involvement of multiple federal agencies with overlapping responsibilities and different policies (NRC, 1994).</p> <h4>Barriers to implementation</h4> <p>One of the most significant barriers to the use of wetlands as a measure to combat coastal flooding and erosion is a lack of public awareness of the flood and erosion protection benefits offered by these ecosystems.  Unless the public is educated on the benefits that wetlands provide, the link between coastal flood and erosion protection and wetland restoration is likely to be unclear.  This will hinder the uptake of these projects as communities press for more tangible, hard defence options, for which the protective benefits are more widely understood.</p> <p>Another barrier to successful implementation is an incomplete understanding of the ability of a degraded wetland to recover, and of the success rates of wetland creation.  We still do not fully understand the needs of wetland plants and animals.  As such, uncertainty also surrounds the effectiveness of wetland restoration activities and whether the full range of ecosystem functions will be restored during wetland repair.  Monitoring of completed schemes will enhance our understanding of wetland restoration.</p> <h4>Opportunities for implementation</h4> <p>Wetland creation can bring about various economic, social, and environmental benefits to local communities.  For example, it has the capacity to improve the productivity of coastal waters for fishing.  Wetland recreation can also create opportunities for eco-tourism and increase recreational opportunities.  Creation of wetlands, especially in or in close proximity to urban areas can even serve to increase awareness of the important functions performed by these habitats.</p> <p>Because wetland restoration meets multiple management objectives – such as habitat protection, public access to environmental and recreational resources and hazard mitigation – and is less expensive and more aesthetically pleasing than some engineering solutions, the approach is likely to find broader public support in the future (Moser, 2000).</p> <p>There is also the opportunity to implement wetland restoration or creation together with hard defences such as dikes or seawalls.  In such a case, the presence of wetlands on the seaward side of the defence leads to lower maintenance costs over the lifetime of the structure (Tri et al., 1998).</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><span lang="EN-US" xml:lang="EN-US" xml:lang="EN-US">The restoration of natural ecosystem services, including flood and erosion protection benefits, largely outweighs any disadvantages. </span></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/example-constructed-wetlands-compensate-urbanization-souther-finland-fin" hreflang="en">EXAMPLE: Constructed wetlands to compensate for urbanization in souther Finland (FIN)</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><em>Main source: </em> Matthew M. Linham & Robert J. Nicholls (2010):<em> </em>TNA Guidebook on '<a href="http://www.unep.org/pdf/TNAhandbook_CoastalErosionFlooding.pdf">Technologies for Climate Change Adaptation'</a> UNEP , 166p.</h5> <h6>Brampton, A.H. (1992) Engineering significance of British saltmarshes in Allen, J.R.L. and Pye, K. (eds.).  Saltmarshes: Morphodynamics, conservation and engineering significance.  Cambridge: Cambridge University Press, 115-122.</h6> <h6>Moser, S.C. (2000) Community responses to coastal erosion: implications of potential policy changes to the National Flood Insurance Programme.  Appendix F.  In Evaluation of Erosion Hazards.  A project of the H. John Heinz II Centre for Science, Economics and the Environment.  Prepared for the Federal Emergency Management Agency, Washington DC.</h6> <h6>Nicholls, R.J. and Klein, R.J.T. (2005) Climate change and coastal management on Europe’s coast in Vermaat, J.E. et al. (eds.).  Managing European Coasts: Past, Present and future.  Berlin: Springer-Verlag, 199-225.</h6> <h6> Nicholls, R.J., Cooper, N. and Townend, I.H. (2007) The management of coastal flooding and erosion in Thorne, C.R. et al. (Eds.).  Future Flood and Coastal Erosion Risks.  London: Thomas Telford, 392-413.</h6> <h6>NRC (National Research Council) (1992) Restoration of Aquatic Ecosystems.  Washington DC: National Academy Press.</h6> <h6>NRC (National Research Council) (1994) Restoring and Protecting Marine Habitat: The Role of Engineering and Technology.  Washington DC: National Academy Press.</h6> <h6>Tri, N.H., Adger, W.N. and Kelly, P.M. (1998) Natural resource management in mitigating climate impacts: the example of mangrove restoration in Vietnam.  Global Environmental Change, 8 (1), 49-61.</h6> <h6>USACE (United States Army Corps of Engineers) (1989) Environmental Engineering for Coastal Shore Protection.  Washington DC: USACE.  Available from: http://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-1204.pdf</h6> <h6>White, P.C.L., Godbold, J.A., Solan, M., Wiegand, J. and Holt, A.R. (2010) Ecosystem services and policy: A review of coastal wetland ecosystem services and an efficiency based framework for implementing the ecosystem approach in Harrison, R.M. and Hester, R.E. (eds.).  Ecosystem Services.  Cambridge: the Royal Society of Chemistry.</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 19:25:50 +0000 giacomo.cazzola 85 at https://coastal-management.eu Reafforestation in upland areas and buffer zones https://coastal-management.eu/measure/reafforestation-upland-areas-and-buffer-zones <span class="field field--name-title field--type-string field--label-hidden">Reafforestation in upland areas and buffer zones</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">Fri, 09/09/2016 - 12:53</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/36" hreflang="en">Erosion</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/58" hreflang="en">Natural flood, runoff, catchment 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>Reafforestation and afforestation refer to to activities where trees are established on lands with no forest cover. The concept of reafforestation is usually used in reference to areas where there was recent forest cover. Reafforestation and afforestation activities, as well as existing forests, can help to reduce the occurrence and intensity of floods.</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>Reafforestation and afforestation refer to to activities where trees are established on lands with no forest cover. The concept of reafforestation is usually used in reference to areas where there was recent forest cover. For areas without an historical record of forest cover, the planting of trees is referred to as afforestation (IPCC 2000). The activities could also include making a conscious decision to maintain forests on lands that would otherwise be handed over for other types of land development, as part of targeted water management interventions.</p> <h4>Benefits</h4> <p>Reafforestation and afforestation activities, as well as existing forests, can help to reduce the occurrence and intensity of floods. Many communities are already harnessing the water benefits of forests. Forest areas in the upper watersheds can help retain water and stabilize slopes, thereby reducing the risks and disaster caused by storms. Deforestation is a major cause of land degradation and soil erosion. With soil erosion, its ability to store and retain water diminishes, which contributes to higher risks of flooding, as the soils are no longer able to reduce the rate and volume of runoff that occur in the event of heavy rainfall and storms. While increase in forest cover is unlikely to significantly affect outcomes of strong flood events in big watersheds or strong, low frequency floods in smaller rivers, it can have a high impact on reducing minor to moderate floods in relatively small and medium-sized watersheds.</p> <p>Trees intercept rainfall and increase infiltration, and the ability of soils in forest areas to store more water and release it through evaporation helps in regulating the water quantity during extreme weather events (CNT & American Rivers 2010). However, intensive reafforestion/afforestation activities may reduce the local total annual runoff and groundwater recharge due to increased water loss through evapotranspiration. Thus, there is a trade-off between a more constant supply of water and a reduction in total available water volume.</p> <p>Planting tree species particularly adapted to the local climate and hydrology can help to predict the impacts on groundwater recharge with higher certainty and thus provide greater choices of the most appropriate interventions.</p> <p>Forests can also reduce the likelihood (or frequency) of landslides, mudflows and avalanches, which can cause extensive damage to infrastructure and inhabited areas vulnerable to floods (EC 2011).</p> <p>Establishing or conserving forests (but also promoting other sustainable land use activities in the watershed) can contribute to improving water quality. Forests improve water quality by reducing sediment in water bodies and trapping or filtering other water pollutants. Along the shores of water bodies, the roots help to stabilize banks against erosion. Forest cover is also an effective way to prevent other pollutants from draining into the watercourse and regulating sediment flow, if distributed throughout the upstream watershed e.g. drinking water supply reservoir (FAO, 2008). Such measures to ensure a high quality drinking water supply have already been put in place in a number of countries across the globe - a third of the world’s hundred largest cities rely on forested protected areas for their drinking water. In fact, well- managed forests often provide clean water at costs lower than those of treatment plants (TEEB 2009).</p> <p>Forests and riparian buffers in particular, also help to mitigate thermal pollution by providing shade to the streams (see Riparian buffers).</p> <h4>Co-benefits</h4> <p>Forests are among GI solutions with the greatest environmental and socio-economic co-benefits. In addition to the immediate benefits that forests have in regulating water quantity and quality, they can also function as carbon sinks, increase pollination for nearby agricultural fields, improve air quality, regulate local climate (including cooling) and help preserve biodiversity. For example, a study from Cascine Park in Florence, Italy, shows that the urban park forest maintained its ability to remove air pollutants over a period of 19 years, removing about 72.4 kg per hectare per year, despite some tree losses due to logging and extreme weather events. Harmful pollutants removed included O3, CO, SO2, NO2, and particulate pollutants, as well as CO2 (TEEB 2011). Increasing forest cover can also open up possibilities for alternative livelihoods and income opportunities through agroforestry, ecotourism and a range of other forest products.</p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Costs</h4> <p>The primary costs of establishing forests include the cost of land, purchasing seeds or saplings and tree planting (Foster et al. 2011). Reafforestation can also take place through natural regeneration. Just like any infrastructure investment, opportunity costs and ongoing maintenance needs should be considered, in addition to the initial cost of investment in GI. The costs of reafforestation/afforestation or forest conservation activities are usually directly dependent on existing alternatives for land use and vary greatly depending on the location.</p> <p>For example, lands in or near major urban centres are likely to be more costly to use for such purposes than those in more remote areas due to demands for competing land uses. They may also yield larger benefits. In the city of San Diego, USA, it was estimated that in 2002 the stormwater retention capacity of the urban forest was 2 million cubic meters. If this forest were lost, it is estimated that providing the same benefit through built infrastructure would cost approximately USD 160 million (American Forests 2003).</p> <p>An important cost consideration is also time lag, which can be substantial for reforestation/ afforestation projects, increasing the overall project costs (TEEB 2009). This makes a particularly strong case for forest conservation as one of the priority interventions to maintain water services provided by trees. Trees take time to mature and be able to deliver the full range of services, in contrast to grey infrastructure, which begins operation as soon as it is created. This can also cause afforestation activities to be evaluated negatively, compared to traditional solutions. Forests are also exposed to a number of less predictable risks that can compromise delivery of water benefits and require additional investment – e.g. wildfires, change in ecosystem services due to climate change and pests. The exact costs of GI activities within afforestation or forest conservation are location specific and dependent on a wide range of variables. The data on exact costs is sparse, but a recent database with 127 GI projects from the European Union found that the costs for reafforestation/afforestation projects ranged from USD 1,300 to USD 2,500 per hectare of forest (Naumann et al. 2011).</p> <p>Where standing forests are a source of delivery of these benefits, and where land development activities threaten the continuity of these, an “action” for these communities to take is to conserve strategic networks of those forests that are most important for the provision of water. Part of that means making sure timber operations are conducted in a way that don’t degrade water resources, choosing alternative land development options, and making a strategic decision to forego potential investments returns to preserve forest cover and associated ecosystem service delivery. Water funds, operating based on the principles of payment for ecosystem services (PES), is just one example of possible approaches to preserve forest ecosystem services.</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-restoring-riparian-forests-bg" hreflang="en">EXAMPLE: Restoring Riparian Forests (BG)</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>CNT & American Rivers (2010). Center for Neighbourhood Technology and American Rivers, The Value of Green Infrastructure. A Guide to Recognizing its Economic, Environmental and Social Benefits.</h5> <h5>EC (2011). European Commission, Directorate-General Environment, Towards Better Environmental Options for Flood risk management, DG ENV D.1 (2011) 236452.</h5> <h5>TEEB (2009). TEEB – The Economics of Ecosystems and Biodiversity for National and International Policy Makers.</h5> <h5>TEEB (2011). TEEB – The Economics of Ecosystems and Biodiversity (2011). TEEB Manual for Cities: Ecosystem Services in Urban Management.</h5> <h5>Foster, J., Foster, H., Lowe, A., and Winkelman, S. (2011). The Value of Green Infrastructure for Urban Climate Adaptation, The Center for Clean Air Policy, (February).</h5> <h5>American Forests (2003). Urban Ecosystem Analysis, San Diego, California. (July).</h5> <h5>Naumann, S., McKenna, D., Kaphengst, T., Pieterse. M. and Rayment, M. (2011). Design, implementation and cost elements of Green  Infrastructure projects. Final report to the European Commission, DG Environment, Ecologic Institute and GHK Consulting. Available from http://ec.europa.eu/environment/enveco/biodiversity/pdf/GI_DICE_FinalReport.pdf.</h5> <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> Fri, 09 Sep 2016 10:53:05 +0000 giacomo.cazzola 84 at https://coastal-management.eu Temporary and demountable flood defences https://coastal-management.eu/measure/temporary-and-demountable-flood-defences <span class="field field--name-title field--type-string field--label-hidden">Temporary and demountable flood defences</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">Thu, 09/08/2016 - 16:04</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 class="field__item"><a href="https://coastal-management.eu/taxonomy/term/35" hreflang="en">Estuarine floods</a></div> <div class="field__item"><a href="https://coastal-management.eu/taxonomy/term/37" hreflang="en">Coastal floods or storm surges</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/58" hreflang="en">Natural flood, runoff, catchment 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/32" hreflang="en">Hold the line</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>A temporary flood barrier is one that is only installed when the need arises (that is, when high flood levels are forecast). A demountable flood defence is a particular form of temporary defence that requires built-in parts and therefore can only be deployed in one specific location. The removable stoplog defence is a particular form of demountable defence applicable only for small openings in a permanent defence. The more commonly adopted gate option for closing off a gap in a floodwall is neither temporary nor demountable, as it is part of the permanent defence and is left in place all the time (albeit normally in an open position).</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://evidence.environment-agency.gov.uk/FCERM/en/FluvialDesignGuide.aspx">Based on kindly provided information by the Environment Agency's Fluvial Design Guide, Chapter 9</a></p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p>Both temporary and demountable defences require a considerable amount of preplanning to ensure that they can provide an effective defence. It is essential that the operational resources, storage facilities and the logistics of deployment are fully appreciated by anyone planning to rely on these types of defence.</p> <h4>Temporary flood barriers</h4> <p>There are many forms of temporary flood barrier, ranging from sandbags to the so-called pallet barrier. These are suitable for deployment in response to a developing flood in situations where there are no permanent defences or where the existing defences are not high enough.</p> <p>Sandbags can be used to provide a degree of protection at the entrances to individual properties. They have also been used successfully to raise the crest level of significant lengths of flood embankment. However, sandbags do not provide a watertight defence and are practical only up to a height of about 0.3m, perhaps 0.5m in ideal circumstances. They require considerable effort to deploy and often prove ineffective.</p> <p>The pallet barrier is a more sophisticated system which is deployable over a length of several hundred metres. It consists of a lightweight structural system which supports an impermeable membrane. The system relies on a reasonably firm and level foundation. The effective use of such sys-tems also depends on the ability to mobilise them fairly quickly in response to a growing threat of flooding. Storage of the necessary equipment reasonably close to the site is therefore essential, otherwise there is a risk that the defence will not be delivered to site and erected in time to prevent flooding (see also the guidance below on demountable defences in this regard).</p> <p>Whereas temporary barriers may seem to offer a viable solution in situations where there is sufficient time to mobilise and erect them, such systems have other potential disadvantages. It is essential to ensure that no significant drains or other flow pathways are present that would compromise the effectiveness of the defence. There are also likely to be issues with parked cars and road closures that may delay the deployment of the defence to the point where deployment is too late.</p> <p>Temporary barriers therefore require a considerable amount of preplanning to ensure that they can provide an effective defence. For any type of temporary defence, it is essential that the operational resources (labour, plant and equipment), storage facilities (access to and from, security, proximity to point of deployment), and the logistics of deployment are fully explored before the commitment to rely upon this approach is made.</p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Demountable flood defences</h4> <p>Demountable flood defences are used where a permanent defence is unacceptable, usually because of the visual intrusion and loss of amenity that a permanent defence would entail. These are relatively new to the UK, but have recently been successfully installed and operated in Shrewsbury and Bewdley on the River Severn, and in parts of north Wales.</p> <p>Time is the key factor concerning the adoption of demountable defences. There must be sufficient advance warning of a flood to allow the defence to be deployed. In addition, the advance warning must be reasonably reliable so as to avoid excessive precautionary deployment of the defences. They are therefore suitable on the middle and lower reaches of the River Severn, for example, where flood conditions can be predicted days in advance, then confirmed with plenty of time to mobilise the erection team. Demountable defences may make use of standard panels, but they often have to be custom-designed to suit a particular location. They rely on built-in foundations for stability and ease of erection.</p> <p>The components of the demountable defence must be stored relatively near to the site to reduce the risk of delays once the decision to mobilise has been made. A skilled erection team is required to ensure that the defence can be safely and securely erected in the limited time available. For practical reasons, the length of a demountable defence is unlikely to exceed a few hundred metres.</p> <p>Whereas demountable defences may seem to offer the ideal solution where visual impact is a key factor, this form of defence tends to be expensive and there will always be a risk that the defence elements are not deployed in time to avert flooding. Theft of defence units, damage to built-in parts and delays in transporting the units to site can all conspire to make deployment problematic.</p> <p>In July 2007, the delivery of the components of a demountable defence at Upton-on-Severn was delayed due to the severe disruption to the transport infrastructure caused by surface water flooding. The defence was not deployed in time and there was considerable flood damage as a result. In fact, had these demountable defences been deployed, they would have been overtopped due to the severity of the flood, but this example illustrates just how important it is to make sure that these defences can be successfully deployed in a flood event.</p></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.aquadam.net/pdf/130_1_ig.pdf">Ogunyoye, F and van Heereveld, M (2002). Temporary and demountable flood protec…</a></div> </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/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/75" hreflang="en">Prevention</a></div> </div> </div> Thu, 08 Sep 2016 14:04:11 +0000 giacomo.cazzola 73 at https://coastal-management.eu Flood storage systems https://coastal-management.eu/measure/flood-storage-systems <span class="field field--name-title field--type-string field--label-hidden">Flood storage systems</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">Thu, 09/08/2016 - 12:24</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 class="field__item"><a href="https://coastal-management.eu/taxonomy/term/35" hreflang="en">Estuarine 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/58" hreflang="en">Natural flood, runoff, catchment 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/72" hreflang="en">Managed retreat</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/66" hreflang="en">Combined approach (grey + green)</a></div> <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>If fluvial systems don't have sufficient room for natural detention of floodwater in the floodplain, the development and management of flood storage within and adjacent to the natural floodplain is recommended and described in more detail in this measure. It addresses aspects like the process of selecting where to locate the flood storage, deciding how much storage is needed, how to measure the storage capacity, selecting appropriate flow control structures, analysing how the works will perform and making sure that the flood storage scheme is safe in extreme floods.</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="http://repository.tudelft.nl/islandora/object/uuid:b10ee43e-def9-4e02-8571-a495bbe1d361?collection=research#">J C Ackers, J M Bartlett (2009): 10 Flood storage works. 28p. In: UK Environmental Agency (2009): Fluvial Design Guide</a> (Contains public sector information licensed under the Open Government Licence v3.0.)"</p></div> <div class="clearfix text-formatted field field--name-body field--type-text-with-summary field--label-hidden field__item"><p>There are two main reasons for providing temporary detention of floodwater:</p> <ul> <li>to compensate for the effects of catchment urbanisation;</li> <li>to reduce flows passed downriver and mitigate downstream flooding.</li> </ul> <p>Although these may be separate drivers for a flood storage scheme, they are in essence identical. The flood storage works are designed to reduce the peak flood flow passed downstream, spreading the overall volume passed downstream over a longer period. Alternative methods of providing this flood protection would be to:</p> <ul> <li>enlarge the river channel;</li> <li>raise the riverbanks;</li> <li>construct floodbanks set back from the river;</li> <li>provide specific protection around flood-prone buildings or groups of buildings.</li> </ul> <p>Providing flood storage is thus one of a portfolio of options for managing and controlling the risk of flooding. In some cases it can provide sufficient flood protection on its own; in other cases it may be chosen in conjunction with other measures.</p> <p>The advantage of flood storage is that the flood alleviation benefit generally extends further down-stream, whereas the other methods benefit only the local area, and may increase the flood risk downstream.</p> <p>If the primary driver for flood storage is to compensate for the effects of urbanisation (see Box 10.1), the objective is normally to detain the additional and faster runoff that results from an increase in the impermeable area. This is then released downstream at a slower rate, designed to mimic the natural runoff from the non-urbanised catchment, avoiding any increase in flood depths and frequencies being propagated downstream.</p> <p>According to Design of flood storage reservoirs (Hall et al, 1993), the provision of flood storage: ‘has much in its favour. The capacity of the reservoir both attenuates the incoming flood peak to a flow that can be accepted within banks by the downstream channel and delays the timing of the flood so that its volume is discharged over a longer time interval’.</p> <p>Hall et al (1993) go on to point out that, where several flood storage reservoirs are deployed in a river basin, their overall effect has to be considered carefully. For example, a flood storage reservoir on a minor tributary could delay the peak of the tributary flood so that it coincides with the peak flood coming down the main stream, thereby making matters worse. It is normally obvious if there is a risk of this occurring, but the application of appropriate hydrological and flood modelling approaches can demonstrate if this is indeed a problem. Such studies need to cover a range of rainstorm and flood scenarios – including the effect of rainstorms moving across the catchment – to ensure that the provision of flood storage at a site is a robust solution that does not have detrimental effects at other locations downstream.</p></div> <div class="clearfix text-formatted field field--name-field-second-descrip field--type-text-long field--label-hidden field__item"><h4>Adaptability</h4> <p>Flood storage works sometimes lend themselves to adaptability to changed circumstances such as:</p> <ul> <li>increased upstream catchment runoff;</li> <li>a change in the vulnerability of downstream communities to flooding.</li> </ul> <p>Increases in catchment runoff may be due to progressive urbanisation or a change in climate, while the downstream vulnerability might change with increased urban development or the implementation of a flood alleviation scheme.</p> <p>Adaptability of the flood storage works could include such features as:</p> <ul> <li>the ability to raise the impounding embankment to increase the flood storage capacity;</li> <li>adjusting the settings of gates or orifices that control downstream releases;</li> <li>if applicable, changing the setting of weirs and gates that admit flows to the reservoir.</li> </ul> <p>At the time when flood storage works are proposed and designed, it is vital to consider:</p> <ul> <li>whether it may be desirable to adapt the design of the scheme in the future;</li> <li>whether any such flexibility should be incorporated into the design.</li> </ul> <h4>Types of flood storage</h4> <p>Flood storage works can usually be described as one of the following:</p> <ul> <li>online – in which the water is temporarily stored within the river channel and its floodplain;</li> <li>offline – in which the water is diverted from the river channel, stored in a separate area (which may be part of the floodplain) and subsequently released back to the river or to another watercourse.</li> </ul> <p>In general, online storage works are normally located in the upper catchment (where the catchment area is modest) while offline storage works are more common on larger rivers with wide floodplains. Some complex flood storage schemes include a combination of online and offline components, de-signed to act in conjunction.</p> <p>Floodplains that are modified to augment their natural flood storage and attenuation characteristics are often described as washlands – a term that can be used in the context of either online or offline flood storage.</p> <p>To learn more about different type of flood storage, click <a href="http://coastal-management.eu/types-flood-storage"><strong>here</strong></a>.</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-reconnecting-lakes-yangtze-river-chn" hreflang="en">EXAMPLE: Reconnecting lakes to the Yangtze River (CHN)</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>Hall, M J, Hockin D L and Ellis, J B (1993). Design of flood storage reservoirs, B014. CIRIA and Butterworth-Heinemann.</h5> <p> </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/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> Thu, 08 Sep 2016 10:24:09 +0000 giacomo.cazzola 64 at https://coastal-management.eu