Storm water runoff is a leading cause of degradation in the water quality of receiving water bodies. Although legislation requires that Environmental Impact Assessments (EIA) are performed and Environmental Management Plans (EMP) put in place for the construction of high density housing developments, there is generally very little evidence that real measures are developed to monitor and actually assess the extent of the impact that construction activities have on the environment during the physical construction stage. The water quality of stormwater runoff from a mixed use catchment including construction sites in Seaward Estates, Ballito, KwaZulu-Natal that enters a coastal forest wetland system was characterised by monitoring programmes established at three study areas. The effect thereof on the quality of the wetland water and sediments was further monitored at five points along the drainage line of the system. The investigation focussed on obtaining representative stormwater samples in order to quantitatively identify pollutant constituents transported within stormwater runoff from construction sites during rainfall events. Storm water runoff event mean concentration (EMC), atmospheric deposition and wetland water and sediment samples were collected over an eight month period. The characterisation of stormwater runoff for this investigation included heavy metals, oxygen demanding substances, sediments and physico-chemical analysis for pH, conductivity and ammonia and nitrates. The majority of contaminant EMC exceeded the South African wastewater discharge general and special limits. The findings from this investigation will provide planners and decision-makers with a greater understanding of the pollution dynamics of construction sites aiding in improved best management practice decisions with regard to minimizing impacts on coastal forest wetlands and water resources. This will lead to improved EMP and stormwater management plans (SWMP) incorporating stormwater pollution prevention plans (SWPPP) for construction sites. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.

M.Sc. (Aquatic Health) / Located largely in a semi-arid part of the world, South Africa’s water resources, in global terms are extremely scarce and limited. (South Africa is one of the 30 driest countries of the world). South Africa is already categorised as water stressed with annual freshwater availability of less than 1700 mm³ /person (the index for water stress) (Blignaut and Van Heerden, 2009). South Africa is a water scarce country due to low rainfall (less than 500 mm per annum, some parts less than 200 mm: the average of 475 mm is well below the global average of 860 mm p/a.) and due to the uneven distribution of its water resources (more than 60% of the river flow arising from only 20% of the land area) which is a direct result of the climate and topography of the country (Davis and Day, 1998). South Africa is a large piece of land, far larger than for instance Germany (population of 82.7 million- Bergman and Renwick, 2003). When compared, Germany has 2169 cubic meters of water available per person while South Africa has only 1208 (Bergman and Renwick, 2003). Compared with another arid country, Australia has a population of 19.1 million and freshwater resources of 18 722 cubic meters per person (Bergman and Renwick, 2003). South Africa has close to the lowest conversion of rainfall to usable run-off from rivers of all the countries in the world (South Africa 8.6%, Australia 9.8%, and Canada 66%) (Bergman and Renwick, 2003). South Africa will also be negatively impacted by both changes in climate and the prevalence and spread of alien invasive species (Blignaut and Van Heerden, 2009). Prosperity for South Africa depends upon the sound management and utilisation of many resources, with water playing a pivotal role. Any decrease in the quality and therefore the usability of water in South Africa by 1% may result in the loss of 200 000 jobs, a drop of 5.7% of disposable income per capita, and an increase of 5% or R18.1 billion in government spending. This will further result in a 1% decrease in the GDP growth rate (Du Toit, 2010). This is reiterated by a number of other studies.

Constructed wetland treatment systems are environmental-friendly and economic technologies for wastewater treatments. The Dapeng Bay National Scenic Area Administration collected the wastewaters from the salty water aquacultural ponds and community households in the adjacent areas and discharged them into salty water type of constructed wetland treatment systems, which is quite rare in Taiwan presently. According to the surveying result of water quality in these constructed wetland treatment systems in previous study, we found that some species of macroalgae Gracilaria, were existed in some units of the wetland systems. Further, we found that the wastewater treatment efficiencies of the constructed wetland systems could be substantially enhanced by the macroalgae. Reviewing some literatures also confirmed that the macroalgae, Gracilaria, can be effectively applied to aquaculture wastewater treatment because it is able to absorb the nutrients and benefits its own growth. Besides, it can reduce the algal bloom caused by excess nutrients. In this study, we explored the macroalgae Gracilaria¡¦s role in those saline constructed wetland wastewater treatment systems. In the laboratory scale study, a constructed wetland model tank was designed to culture Gracilaria as a way to explore the situation of wastewater treatment. The experimental results showed that when cultured in the still water system, the macroalgae, Gracilaria, was able to increase both of the levels of dissolved oxygen and pH in wastewater. Moreover, when it was cultured in its biomass density of 10 g/L for 4 days, the removal efficiency of chlorophyll-a concentration could ideally reach to 79.10 ¡Ó 7.62 %, while the total nitrogen, and total phosphorus could reach to 47.10 ¡Ó 25.93 % and 60.49 ¡Ó 45.29 % respectively. However, the reduction of ammonia nitrogen concentration was found rather obvious only one day after culture. Whereas, when the species of Gracilaria was cultured in the continuous flow system, we found that there were significant difference in the test result of the turbidity, chlorophyll-a, and BOD in the experimental group with addition of Gracilaria. After testing the concentrutions of chlorophyll-a over a long period of time, we found that the chlorophyll-a concentration were markedly increased when Gracilaria was not added. On the contrary, the chlorophyll-a concentration was remained stably when Gracilaria was added. When it comes to the nitrogen removal, we found that the removal efficiency of ammonia nitrogen in the experimental group could reach up to 92.27 ¡Ó 3.82 % in average. Other than that, it was found obvious decrease of the ammonia nitrogen concentration on the first day of culture. As to the test of soil¡¦s impact on the phosphorus removal, we found that the removal efficiency in the experimental group was higher than the group without soil. Therefore, the removal efficiency was found obviously higher when there was soil. In the continuous flow system, when the species of Gracilaria was added, the removal efficiency of total nitrogen and total phosphorus in the model tank could reach averagely up to 75.23 ¡Ó 2.46 % and 53.96 ¡Ó 11.18 %, respectively. Comparing the experimental results by growth of Gracilaria for water quality with laboratory study and the saline constructed wetland systems in the Dapeng Bay, we found that the removal efficiencies of contaminants and nutrients could be enhanced by Gracilaria.

A constructed wetland was built in southern Taiwan in 2007 for local stream water purification and ecosystem improvement. The inflow rate was approximately 1,350 m3/day. The wetland influents were mainly from the local streams containing secondary wastewater from hog farms located in the upper catchment of the wetland and drainage water from the farmlands. The influent water contained organic contaminants and nutrients, which needed to be removed. The mean measured hydraulic loading rate, hydraulic retention time, water depth, and total volume of wetland system were 0.1 m/day, 5.5 days, 0.7 m, and 7,800 m3, respectively. In this study, water, sediment, and plant samples were collected and analyzed quarterly for each wetland basin during the two-year investigation period. Results show that more than 77% of total coliforms (TC), 78% of biochemical oxygen demand (BOD), 88% of total nitrogen (TN), and 96% of ammonia nitrogen were removed via the constructed wetland system. Thus, the wetland system has a significant effect on water quality improvement and is able to remove most of the pollutants from the local stream through natural attenuation mechanisms. Results from the ecological investigation show that more than 50 different plant species and 45 different animal species were observed in the wetland system although this wetland had been created for less than four years. Except for stream water quality improvement and rehabilitating the natural ecosystem, this wetland also offered more water assessable eco-ponds and eco-gardens for public. This constructed wetland has become one of the most successful multi-function constructed wetlands in Taiwan.

Loss of wetland habitats across the nation is staggering and continues, especially in urbanizing areas. Thus, wetland restoration has become a priority. However, questions remain regarding system function and biotic communities. We studied a constructed floodplain wetland complex near Dallas, Texas. We sought to improve understanding of wetland ecosystem development under the influence of different approaches to wetland restoration in an urbanizing landscape. In the wetland complex, 10 constructed sloughs, approximately 70m by 15m, were designated for this study. Our experiment monitored the establishment of aquatic plant and invertebrate communities under different experimental conditions. In 5 sloughs, 5 native perennial hydrophyte species were transplanted in blocks in each slough, with the remaining 5 sloughs unplanted. Portions of each slough were caged to determine the effects of protective caging. Using 1m2 caged and neighboring uncaged areas as quadrats, we sampled vegetation and the invertebrate community over two years to determine the effects of restoration treatmentsSlough planting did not result in statistically different levels of plant cover. However, invertebrate abundance was greater in planted sloughs, and plant composition was different, comprised more of perennial species in planted sloughs than in unplanted sloughs. Caging did not have an effect on plant or invertebrate communities. However, changes due to time resulted in significant increases in plant cover and invertebrate abundance and shifts in community composition. Four of 5 transplanted species were emergent growth forms. Emergent cover and the remaining species, Potamogeton nodosus, a floating-leafed plant, accounted for invertebrate community variation. Transplanted emergent species did not fare well, though other emergent species did colonize the site, along with widespread coverage by submerged Najas guadalupensis. Potamogeton spread rapidly, colonizing unplanted sloughs, and this will likely affect community development across the site. Plant and invertebrate richness values were low, likely due to hydrological extremes and the short period of time since construction. Water level fluctuations resulted in plant communities dominated by obligate wetland plants, though drought stress took a toll on survival of plants and invertebrates in late summer. Community development and system function were dependent mostly upon time and hydrology. on the communities.

The Dapeng Bay National Scenic Area will be planned as an interna-tional level tourism site. In order to improve the water quality in bay area, the administration authority has removed oyster farm. However, sewage and aquaculture wastewater from the communities and fish ponds around the bay area were still discharged continuously. After careful assessment, The Dapeng Bay National Scenic Area Administration authority decided to use constructed wetlands to treat such kinds of wastewater. In this study, the treatment efficiencies of Datan Constructed Wetland Park were investigated. According to the experimental results, we found that the remove efficiencies of SS, Chl-a, and TOC were not good enough, while the other parameters, such as OP, TP, NO2-, and NO3- their all re-moval efficiencies were all above 40¢H.The removal efficiencies of NH3, TKN and TN were all above 60%. However, the removal efficiencies of turbidity and BOD were found equal to 30%. Generally, TN was removed by the process as of nitrification and denitrification, but the nitrification of the subsurface flow¡]SSF¡^part of wetland was perforated worse, which caused the org-N and NH4+-N was not availably to become the NH3, NO2- and NO3-. Because of this reason, the removal effect of Org-N was not very significant. The parameter of TOC was affected by the fixation of CO2 through photosynthesis of autotrophs, and the respiration and denitrification of heterotrophs. The sediment also could provide organic carbon source for denitrification. Photosynthesis and carbon source would cause the re-moval efficiency of TOC become worse than synthesis. In the wetland, the decrease rate of salinity was found above 20¢H.

Thesis (M.S.)--University of Hawaii at Manoa, 2003. / Includes bibliographical references (leaves 99-106). Also available via World Wide Web.

Thesis (M.A.)--Ohio University, November, 2009. / Release of full electronic text on OhioLINK has been delayed until September 1, 2014. Title from PDF t.p. Includes bibliographical references.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

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