A predicted loss of agricultural rice-wetlands and increasing urbanization and development threatens the remaining freshwater wetlands along the upper Texas coast. To avoid, minimize, and mitigate wetland loss, the U.S. Army Corps of Engineers (Corps) is directed to enforce Section 404 of the Clean Water Act (1975 amendment) by administering permits for development. Furthermore, a 1990 Memorandum of Agreement (MOA) between the Corps and the U.S. Environmental Protection Agency (EPA) proposed a national goal of no net wetland loss (NNL). My goals were to identify the frequency of occurrence of freshwater wetland loss due to dredge or fill, assess final plans to mitigate wetland loss, and verify the persistence of the created compensatory wetlands. I created a database of 96 individual, Section 404 permits issued from 1981 to 2001 in the counties of Chambers, Hardin, Jefferson, Liberty, Montgomery, Orange, and San Jacinto (Galveston District Office, U.S. Army Corps of Engineers). Descriptive statistics were calculated for permit characteristics in relation to issue date (pre- or post-NNL). Public comments received from national and state agencies were rank ordered against mitigation plan type to determine Spearman's Rank Order Correlation Coefficient. Visual identification (via site visits and 1996 aerial photos) was used to validate compensatory wetland persistence. Shoreline protection of private property and oil and gas drilling (64% of permit applicants and 59% of impacts) had the greatest effect on wetland loss in the region, particularly Chambers, Jefferson, and Montgomery counties. Overall, 79.3 ha of freshwater wetlands were gained; however, gain was overestimated due to large projects for habitat enhancement. Permits issued post-NNL were more likely to have formal mitigation plans (58% vs. 13% pre-NNL) and allowed no net wetland loss. Although agency comments recommending more formal mitigation plans increased after NNL, only a weak positive correlation was detected (Spearman's r less than or equal to 0.4). Six of seven created wetlands remained in existence through 2006 though they are freshwater ponds replacing more diverse aquatic systems. I recommend the development of a comprehensive method to track wetland loss, mitigation, and changes in watersheds over time.

Wetland-based treatment systems are often implemented as a method to remove unwanted substances from contaminated groundwater. Wetlands are effective due to the high biological activity that naturally takes place in the rhizosphere and soil. In support of a demonstration surface wetland system at a site in Columbus, Georgia, laboratory-scale wetland systems were designed to study the effect of different carbon sources and their biodegradability, COD:N ratio and temperature on the rate and extent of nitrate reduction of nitrate-bearing groundwater. Nitrate reducing bacteria are ubiquitous in surface and subsurface wetlands but a major limiting factor for these systems is carbon availability. Two major carbon sources were investigated in both continuous-flow and batch systems: a natural source, hay and a commercial source, MicroC GTM, a concentrated carbohydrate mix. Between these two carbon sources, the nitrate removal rate was not significantly different as long as sufficient biodegradable carbon was provided. The effect of both hydraulic retention time (HRT) and COD:N ratio on nitrate removal were investigated in continuous-flow systems. The specific nitrate removal rate in open to the atmosphere batch reactors was estimated at 0.55 mg N/mg biomass VSS-day. The effluent nitrate concentration in a continuous-flow system maintained with an HRT of 5 days at room temperature (22 to 23°C) was less than 3 mg nitrate-N/L. The COD:N ratio was kept at 6:1 for the majority of the experiments (approximately twice the theoretical requirement) to ensure sufficient carbon loading. Lower COD:N ratios of 5, 4, 3, 2, 1, and 0.5 were also investigated in the continuous-flow system and the minimum required carbon loading to achieve an effluent nitrate concentration below 10 mg N/L for an influent groundwater nitrate concentration between 65 and 70 mg N/L was determined to be 5:1 COD:N. The effect of temperature on the nitrate removal rate was also investigated at 22, 15, 10 and 5°C. As expected, the rate of nitrate reduction decreased with the decrease in temperature, especially below 10°C. Overall, the surface wetland is a feasible solution to treating nitrate-bearing groundwater even at relatively low ambient temperature values, provided that sufficient, biodegradable carbon is present.

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Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 208-216). Description: xiv, 216 leaves : maps ; 29 cm.

MENVSC / Department of Ecology and Resource Management / Wetlands are amongst the world’s most important ecosystems providing many direct and indirect benefits to local communities. The majority of South Africans residing in rural areas depends mostly on natural resources for their livelihood. However, wetlands in South Africa continue to be the most threatened ecosystems primarily due to unsustainable use and poor resource management. Additionally, the history of South Africa has been characterised by exclusion of local communities in the process of decision-making and general management of natural resources. The aim of the study was to investigate possible challenges affecting the management of Thulamela wetlands by assessing the level of interaction and conflicting interest amongst participating stakeholders, including role of wetlands on local communities for possibly improved management scenarios. The study used questionnaires, interviews and observations to capture data on the local communities and management stakeholders. Seven wetlands within Thulamela were selected as study areas and the study population was selected based on their specialised expertise, involvement, and closeness to wetlands. Data was analysed using SPSS, Microsoft Excel and also using thematic analysis in NVIVO. The results show that selected wetlands are highly beneficial in supporting the local communities. Based on the socio-economic and demographic characteristics (family size, age, gender, and employment status) measured, the study deduced that unemployment rate or low income of the respondents is the main contributor to an increase dependency on wetland utilization. Additionally, the results revealed that unregulated use and excessive agricultural practices such as cultivation and livestock grazing are common in all study areas, hence further degradation of these wetlands. One of the findings from the study was the destruction of wetlands through expansion of human settlement. The population increase in the areas was found to be major drivers of socio-economic challenges causing people to spread through and exploit wetlands. Consequently, human settlement along the wetland area has resulted in the extensive clearance of natural wetland vegetation. Furthermore, the results show that there is poor wetland information transfer to the local communities most likely due to none/or insufficient outreach programmes. The current management arrangements and structures for selected wetlands are not being practiced through the unequal representation amongst management stakeholders and poor inclusion of local communities in management processes. Additionally, there are currently no openly known active platforms provided upon which stakeholders are able to air their views on wetlands management issues. The findings further show differences in perceptions amongst wetlands users, non-users and management stakeholders. The management stakeholders have a relatively strong focus on livelihood and environmental problems, they regard rules and regulations on wetland use’ as a relatively central variable. On the other hand, the local communities are currently more concerned about the benefits they receive from the wetlands than the conservation of those systems. The study also revealed unequal representation amongst participating management stakeholders. The findings show poor interaction between the management stakeholders and the local communities; differences in perceptions amongst resource users, non-users and managers; exploitation of wetlands resources; poor wetlands information transfer. The results suggest that centralised top-down rules and regulations on wetland use are not sufficient for maintaining the wetland ecosystem and this poses a challenge to sustainable wetland management. Therefore, there is a need to develop shared understanding through bottom-up approaches to wetland management that are nested within national regulatory frameworks, ideally combined with awareness building and knowledge sharing on the ecological benefits and management of wetland. / NRF

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