The Envisaged Climatic Changes and the Failures of Water - Essay Example

Stromwater Progress Report Contents List of Figures 3 Introduction: 4 Objectives of WSUD 8 Climate change impacts on Stromwater quantity and quality In Queensland Australia 8 Types of WSUD Infrastructure 10 a. Constructed Wetlands 10 Description 10 Functions of Constructed Wetlands 12 b. Bioretention Basins 13 Description. 13 Functions of bioretention Basins 14 c. Swales and buffer strips. 16 Functions of Buffer strips and Swales 17 List of Figures Figure 1: Typical Urban Water Cycle 7 Figure 2:Newly planted constructed wetland 11 Figure 3: Same Wetland After 2 years 11 Figure 4: A typical Horizontally Constructed Wetland 12 Figure 5: A typical Bioretention Basin layers 14 Figure 6: Typical Vegetated Swales at a driveway crossing 16 Figure 7: A Typical roadside kerbs 17 Introduction: Water Sensitive Urban Design (WSUD) in Queensland Australia Australia is a country where most of its population lives in urban cities and towns. The effect is of these urban areas grow far beyond the actual limit of the developed areas, particularly through: The need for a large upstream land mass to capture, store and supply water to this urban areas The discharge to the downstream collecting water (rivers, lakes, coastal areas etc) of the discharged stormwater The momentous modification and augmentation of the natural hydrological features and the related ecological processes in the upstream, downstream and within the urban areas Some of the factors that complicate these impacts include rise in population, the gradual realization of the finite resources of supplying and receiving water in these urban areas coupled with the climate change. According to a report by Joint Steering Committee for Water Sensitive Cities (JSCWSC), climate change is one of the biggest challenges facing Australia (JSCWSC, 2009). The fact that the Australian states depend majorly on surface means that the country is highly susceptible to climate change. According to (James A. O’Neill II, 2010), the envisaged climatic changes, may likely increase the failures of water, stormwater, and physical infrastructure if certain measures are not put in place both in the design and planning on modifications and improvements of the existing systems. For instance, the current stormwater infrastructure in the Queenland Australia was designed over 30 years ago, and so far the better part of it has exceeded their useful life(Linmei Nie, 2010). The problem is more pronounced in urban areasSignificant changes in climate and the resultant impacts are largely visible, and are predicted to become more assertive. The climatic changes have caused the need for change in many facets of human life; society, environment, and developmment patterns today in days to come. This has affected the design, planning, and operations of human activities, human activities and general preparedness of emergency actions. It is projwected that in the next century, there will remarkable changes in both intensity and pattern of precipitation, climate, storm (Linmei Nie, 2010). In order to address the above, the Australian, State and Territory Governments through the National Water Initiative (NWI) has embarked on a comprehensive national strategy aimed at boosting water management throughout the country. The program encompasses a range of water management concepts that promotes the adoption of the preeminent approaches to the management of water in the Queensland State. In this context, the NWI is aimed at facilitating an efficient management of water in the urban regions. The concept is called Water Sensitive Urban Design (WSUD); incorporating the integrated design of the urban water cycle, from the supply of water, to the management of storrmwater, wastewater and ground water, through urban design and environmental conservation (Association Stormwater Industry, 2011). By definition, Water Sensitive Urban Design (WSUD) refers to an incorporated design and development of an urban water cycle, integrating water supply, storm water, groundwater and wastewater management, environmental protection and urban design through site layout and design and building design, with constructed and installed elements that offer on- site water quality treatment. WSUD provides alternative techniques to the traditional passage of water approach through the use of waterways and pipes. According to (Ministry of the Environment- Canada, 2010), stormwater is defined as water, or any other precipitation form that has reached the ground or any surface. Urban storm water runoff mostly involves many individual source flow area that ultimately join in a particular drainage area before flowing into the receiving water. Most of the urban surface run- off comes from roofs, driveways, parking lots, and sidewalks (Pitt, 2003). Depending on the energy of the rain and the properties of the pollutants debris, surface run-off may carry these pollutatnts from the sorce area to the drainage systems, or over impervious areas connected to the drainage system. According to (Pitt, 2003), past studies indicate that huge proportion of these stormwater poulutants especially the toxicants are related to the automobile use and repairs and most of these form the large portion of the suspended particulatters in the stormwater (non- filterable matter). The removal of most of these particulates from the surface run off water is dependent on the particular properties of these pollutants, for instance the size and settling rates. Water Sensitive Urban Design (WSUD) is one of the concept used in combating pollution on surface run off water is the integration of urban water cycle, consisting of ground water, stormwater, water supply and waste water in thex initial and progressive urban design with the aim of mitigating environmental degradation(JSCWSC, 2009). WSUD emphases on the benefits of stormwater as a water resource and an environmental equity rather than what is viewed as a nuisance which should be disposed of quickly to the detriment of the receiving watercourses. Managing stormwater and urban runoff does not only tackle the challenges of storm but helps to improve the social and environmental amenity of a town landscape thereby minimizing the capital, operation and maintenance costs of the runoff drainage infrastructure. Figure 1 shows a typical stormwater flow in urban areas. Figure 1: Typical Urban Water Cycle Adapted from (JSCWSC, 2009) Objectives of WSUD The general objectives of Water Sensitive Urban Design include: Minimizing the portable demand for water through the integration of water efficient infrastructure, fittings and appliances coupled with a fit- for- purpose approach to the utilization of potential alternative water sources. Treatment stormwater to meet the set objectives of water quality prior to reuse or discharge Preserve or restore the natural hydrological catchment regimes Promote a significant extent of self-sufficiency of water through maximizing of the utilization of water sources from within thus minimizing potable water inflows and outflows from the development. Climate change impacts on Stromwater quantity and quality In Queensland Australia National flooding is arguably the most expensive disaster especially when we consider the recent flooding in Victoria, Queensland and NSW. Climate change aggravates the prevailing challenges with both surface and underground water quality in Australia. The impacts of climate change on water quality can be discussed in terms of changing physical and chemical processes, alteration of the microecology, and the influence on both the health and economic aspects of humans (scitech, 2009). The uncertainty in climate change scenarios and the gaps in the relevant knowledge to the impacts of a changing climate on waters resources make it hard to precisely predict the potential changes in water systems. In addition, different water resources will react in different manners to climate change; therefore it is prudent to counter the possible consequences (Waters, 2010). Types of WSUD Infrastructure a. Constructed Wetlands Constructed wetland systems refer to shallows extensively “vegetated water bodies” that utilize lengthy detention, fine filtration and finally biological uptake of pollutants from stormwater. Constructed wetland are made up of an inlet basin (sedimentation zone), followed by a macrophyte zone, and finally a high flow shunting channel. The macrophyte basin created a region of extended retention through the shallow average depth of between 0.25m to 0.5m, creating a water detention of between 48 to 72hrs depending on the target pollutant and desired operation (Linmei Nie, 2010). Description These constructed wetlands also perform another function of controlling the water flow by increasing during the heavy rain periods, and ultimately releasing gradually the stored water after the rains subside. For higher results, these wetlands are usually constructed with a higher water detention capacity or extra retention. In case the flow of the stormwater over the filtration zone exceeds the design capacity or operational flow of the constructed wetland, the excess stormwater is goes around the macrophyte zone through channels thus protecting the wetland vegetation as well as ensuring that the trapped sediments and pollutants are not suspended (JSCWSC, 2009). Figure 2 and shows shows a typical constructed wetland at various stages. Figure 2:Newly planted constructed wetland Figure 3: Same Wetland After 2 years Adapted (Hua, 2003) Constructed wetlands can be classified into two broad categories i.e. vertical flow systems and horizontal flow systems. In the horizontal type the stormwater is fed into the system through inlets and flows horizontally through a sloppy bed to the outflow. In vertical flow system stormwater is intermittently fed and moves vertically down via a set of drainage pipes. Figure 4: A typical Horizontally Constructed Wetland Adapted from (Hua, 2003) Functions of Constructed Wetlands The primary function of constructed wetlands is to clean various kinds of water including agricultural, industrial, stormwater and municipal. Unlike a natural wetland, a constructed wetland is created in a non-wetland ecosystem such as a former terrestrial environment for the sole purpose of cleaning out the pollutant or contaminant. Ideally, the critical role of the plants contained in the wetland in relation to water purification is the removal of the physical impurities. These emergent plants offer large surface areas for the growth of the microbes which assist in the slowing (Hua, 2003) down of the water flow thus boosting the rate of settling and trapping of the physical pollutants and ultimately increasing the water transparency. The wetland plant also plays a key role in preventing the eutrophication of wetlands thus enabling the retention and removal of nutrients. Studies have shown that constructed wetlandsare effective in treating wastewater containing ammonium compounds, phosphate and nitrate elements as well as reducing organic pollutants, pathogens and heavy metals (Hua, 2003). For sustainable results, constructed wetlands can be constructed by the designing objectively to attain the ultimate goal through close monitoring to assess the performance of the objectives set. b. Bioretention Basins Bioretention Basins refers to a set of infiltration devices adopted for infiltration and treatmentof stormwater runoff. A Bioretention basin is composed of a set of layers, which treat the stormwater as it filters through. The basins can be constructed as stand- alone structures of treating stormwater or as part of the broad stormwater management practice. Description. Bioretention basins or rain use shallow depression of conditioned soil covered with a layer of mulching to retain, filter and treat the surface stormwater.Bioretention Basins they offer flow control and water quality treatment function in addition to the filtration of the storm water to boost run off treatment in both small and medium flow levels. Based on design, Bioretention basins off retention of runoff water through filtering and trapping of suspended solids as well as absorbing and filtering the soils and plant materials. Figure 5: A typical Bioretention Basin layers Adapted from (Storey, 2009) Functions of bioretention Basins Bioretention basins or rain gardens offers flow control and performs water quality treatment role. The rate and efficiency of pollutant removal in the Bioretention pollutants can be optimized, relative to the flow control functionality, via the adoption of extended water retention component of the basin for low and medium water runoff situations. The rate and quantity of pollutant removal in a Bioretention basin is based on the filtration media used in the structure, depth of the underflow drains, quantity of the infiltration occurring in the surrounding adjacent soils and the relative magnitude of the extended hold up component of the Bioretention basin. By design, Bioretention are aimed at capture, filtering and retain stormwater in recessed, infiltration processes and absorption to get rid of the pollutants from the flow stream. The removal of pollutants within the basins is through a number of techniques such as through sedimentation of sediments, filtration of water through the filtering media and finally through biological processes. In most of these cases, Bioretention basin systems can provide a footprint when compared with other constructed wetland measures, however their utilization on a wider scale is complicated and thus other appropriate devices to this extent may be beneficial. In larger scale applications, it good practice to integrate to incorporate the pretreatment measures (such as swales and vegetated strips) upstream of the Bioretention system so as to capture and filter sediment as well as minimizing the maintenance frequency rate of the Bioretention basin downstream. The size of the Bioretention area or rain garden is determined by the volume of runoff that can be filtered or stored, as well as the treatment benefits associated with the basin. When the volume of the inflow exceeds the capacity of the retention area, additional stormwater devices may be necessary to handle the excess design storm. Since the rain garden/ Bioretention area is basically utilized to boost infiltration, it is prudent to place it in area where there is natural filtration and not areas where water naturally puddles, for instance it is wrong to have the Bioretention basin over a septic systems. c. Swales and buffer strips. Swales and buffer strips to refer to structures used in conveying stormwater through underground pipe drainage and enable the removal of both coarse and medium sediments. Description of Swales and Buffer strips Vegetated swales are often used in conjunction with buffer strips and Bioretention systems. Swales slowly convey water downstream through the utilization of overland flow and gentle slopes. Swales and buffer strips helps in separating impervious regions from downstream water course, thereby protecting waterways from destruction through frequent torrential rainfall thereby reducing the water velocity as compared to piped systems (Storey, 2009). Figure 6: Typical Vegetated Swales at a driveway crossing Adapted from (James A. O’Neill II, 2010) Buffers and buffer strips refers to patches of vegetation cover through which stormwater passes through while moving from the inlet to the discharge point. Buffer strips minimize the sediments loads by allowing water to pass through the vegetation cover. The vegetation slows down the velocities of flowing surface stormwater thus allowing the coarse sediments to be retained. With this need for a uniform surface distribution flow, buffers are often positioned to treat and clean road surface runoff in cases where the surface runoff is flowing through flush kerbs or regular kerbs with cut outs. In these cases, the buffers become part of the roadside swale system (James A. O’Neill II, 2010). Roadside kerbs are example of buffer strips and are constructed alongside pave highways as shown in figure 7 below. Figure 7: A Typical roadside kerbs Adapted from (JSCWSC, 2009) Functions of Buffer strips and Swales Swales offer both flow conveyance and storage in the vegetation and the water quality treatment within the Bioretention area. This buffer area offers optimum water quality treatment rates and efficiencies to moderate stormwater flows. Inflow capacity may be achieved also if the cross sectional area of the swale is increased provides a wider surface area of infiltration and removal of sediments in relation to the flow rate. Swales are constructed with average longitudinal slopes of between 1 and 4% so as to maintain flow capacity without increasing the speed of flow. pollutant removal in swales and buffer strips is achieved through sedimentation of the suspended solid particles, filtration of water through the filtration media and removal of organic wastes through biological processes. The rate and amount of removal of pollutants in these structures is based on landscape slope, plant species used filter media used and the hydraulic retention time achieved in the system. References [1]. Association Stormwater Industry. (2011, April 12). The 2011 Queensland floods: The personal impact. Retrieved September 7, 2013, from http://www.aprs.com.au/australian-water-management-news/the-2011-queensland-floods-the-personal-impact [2]. Hua, S. C. (2003, February). Wetlands International- Malaysia. Retrieved September 6, 2013, from The use of constructed wetlands for wastewater treatment: http://www.wetlands.org/LinkClick.aspx?fileticket=rh7DSmDahzw%3D&tabid=56 [3]. James A. O’Neill II, P. (2010). Climate Change’s Impact on the Design of Water, Wastewater, and Stormwater Infrastructure. Retrieved August 05, 2013, from hydrologydays: http://hydrologydays.colostate.edu/Papers_2010/ONeill_paper.pdf [4]. JSCWSC. (2009, June). Evaluating Options for Water Sensitive Urban Design-ANational Guide. Retrieved September 6, 2013 [5]. Linmei Nie, M. V. (2010). Overview of climate change effects on urban stromwater. Retrieved August 05, 2013, from prepared-fp7.: http://www.prepared-fp7.eu/viewer/file.aspx?fileinfoID=283 [6]. Ministry of the Environment- Canada. (2010). Policy Review of Municipal Stormwater Management in the Light of Climate Change – Summary Report. Retrieved August 05, 2013, from Government of Canada: http://www.ene.gov.on.ca/stdprodconsume/groups/lr/@ene/@resources/documents/resource/stdprod_082453.pdf [7]. Pitt, R. (2003). Sources of Stormwater Pollutants, Including Pollutant Buildup and Washoff. Retrieved August 05, 2013, from http://rpitt.eng.ua.edu/SLAMMDETPOND/WinSlamm/Ch3/M3.html [8]. scitech, E. (2009). Environmental Assessment. Retrieved September 10, 2013, from http://water.epa.gov/scitech/wastetech/guide/stormwater/upload/2006_10_31_guide_stormwater_usw_b.pdf [9]. Storey, B. J. (2009, September ). American Association of State Highway and Transportation Officials . Retrieved September 10, 2013, from Texas Transportation Institute: http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP25-25(53)_FR.pdf [10]. Waters, S. P.—H. ( 2010 , October). Department of Environment and Resource Management (State of Queensland). Retrieved September 09, 2013, from Water Quality and Planning: http://rti.cabinet.qld.gov.au/documents/2010/oct/state%20planning%20policy%20for%20healthy%20waters/Attachments/guidelines%20spp-healthy-waters%5B1%5D.pdf Read More

According to (Ministry of the Environment- Canada, 2010), stormwater is defined as water, or any other precipitation form that has reached the ground or any surface. Urban storm water runoff mostly involves many individual source flow area that ultimately join in a particular drainage area before flowing into the receiving water. Most of the urban surface run- off comes from roofs, driveways, parking lots, and sidewalks (Pitt, 2003). Depending on the energy of the rain and the properties of the pollutants debris, surface run-off may carry these pollutatnts from the sorce area to the drainage systems, or over impervious areas connected to the drainage system.

According to (Pitt, 2003), past studies indicate that huge proportion of these stormwater poulutants especially the toxicants are related to the automobile use and repairs and most of these form the large portion of the suspended particulatters in the stormwater (non- filterable matter). The removal of most of these particulates from the surface run off water is dependent on the particular properties of these pollutants, for instance the size and settling rates. Water Sensitive Urban Design (WSUD) is one of the concept used in combating pollution on surface run off water is the integration of urban water cycle, consisting of ground water, stormwater, water supply and waste water in thex initial and progressive urban design with the aim of mitigating environmental degradation(JSCWSC, 2009).

WSUD emphases on the benefits of stormwater as a water resource and an environmental equity rather than what is viewed as a nuisance which should be disposed of quickly to the detriment of the receiving watercourses. Managing stormwater and urban runoff does not only tackle the challenges of storm but helps to improve the social and environmental amenity of a town landscape thereby minimizing the capital, operation and maintenance costs of the runoff drainage infrastructure. Figure 1 shows a typical stormwater flow in urban areas.

Figure 1: Typical Urban Water Cycle Adapted from (JSCWSC, 2009) Objectives of WSUD The general objectives of Water Sensitive Urban Design include: Minimizing the portable demand for water through the integration of water efficient infrastructure, fittings and appliances coupled with a fit- for- purpose approach to the utilization of potential alternative water sources. Treatment stormwater to meet the set objectives of water quality prior to reuse or discharge Preserve or restore the natural hydrological catchment regimes Promote a significant extent of self-sufficiency of water through maximizing of the utilization of water sources from within thus minimizing potable water inflows and outflows from the development.

Climate change impacts on Stromwater quantity and quality In Queensland Australia National flooding is arguably the most expensive disaster especially when we consider the recent flooding in Victoria, Queensland and NSW. Climate change aggravates the prevailing challenges with both surface and underground water quality in Australia. The impacts of climate change on water quality can be discussed in terms of changing physical and chemical processes, alteration of the microecology, and the influence on both the health and economic aspects of humans (scitech, 2009).

The uncertainty in climate change scenarios and the gaps in the relevant knowledge to the impacts of a changing climate on waters resources make it hard to precisely predict the potential changes in water systems. In addition, different water resources will react in different manners to climate change; therefore it is prudent to counter the possible consequences (Waters, 2010). Types of WSUD Infrastructure a. Constructed Wetlands Constructed wetland systems refer to shallows extensively “vegetated water bodies” that utilize lengthy detention, fine filtration and finally biological uptake of pollutants from stormwater.

Constructed wetland are made up of an inlet basin (sedimentation zone), followed by a macrophyte zone, and finally a high flow shunting channel.

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