RESUMO
The collaborative approach for sustainable management of watersheds is built on engagement of diverse stakeholders. Climate variability and anthropogenic activities increasingly impose challenges to successful management, as do contrasts in stakeholder perceptions about those processes. To assess differences in perceptions about watershed issues, we conducted a focus group meeting of expert stakeholder groups from research institutions, and state and federal agencies in the management of Cimarron River Watershed, Oklahoma. We employed the Strengths, Weaknesses, Opportunities, and Threats (SWOTs) approach to identify important issues, and the analytic hierarchy process to rank the perceptions of these groups. We found incongruity between these two groups over internal factors (SW) and external factors (OT) risking sustainable watershed management. External threats such as climate change dominated the research group perceptions, whereas internally prevalent weaknesses such as inability to track water use and lack of a common platform to share scientific data, dominated the government group perceptions. Despite these differences, both groups identified the negative aspect (W + T) as dominant over the positive aspect (S + O), which suggests a pessimistic watershed management future, with risks prevailing over the opportunities. We see this particular congruity of these two stakeholders as an opportunity to initiate a collaborative approach to watershed management in Oklahoma. We also note that the most important factor from each group corresponds to a relatively modest importance from the other group, and therefore suggests the possibility of cooperation rather than conflict in management goals should collaborative watershed management become established in the watershed.
Assuntos
Conservação dos Recursos Hídricos , Pesquisa/organização & administração , Rios/química , Conservação dos Recursos Hídricos/legislação & jurisprudência , Florestas , Órgãos Governamentais , Humanos , Oklahoma , Percepção , Formulação de Políticas , Competência Profissional , Pesquisa/legislação & jurisprudênciaRESUMO
Nutrient discharge into peri-urban streams and reservoirs constitutes a significant pressure on environmental management, but quantitative assessment of non-point source pollution under climate variability in fast changing peri-urban watersheds is challenging. Soil and Water Assessment Tool (SWAT) was used to simulate water budget and nutrient loads for landscape patterns representing a 30-year progression of urbanization in a peri-urban watershed near Tianjin metropolis, China. A suite of landscape pattern indices was related to nitrogen (N) and phosphorous (P) loads under dry and wet climate using CANOCO redundancy analysis. The calibrated SWAT model was adequate to simulate runoff and nutrient loads for this peri-urban watershed, with Nash-Sutcliffe coefficient (NSE) and coefficient of determination (R2) > 0.70 and percentage bias (PBIAS) between -7 and +18 for calibration and validation periods. With the progression of urbanization, forest remained the main "sink" landscape while cultivated and urban lands remained the main "source" landscapes with the role of orchard and grassland being uncertain and changing with time. Compared to 1984, the landscape use pattern in 2013 increased nutrient discharge by 10%. Nutrient loads modelled under wet climate were 3-4 times higher than that under dry climate for the same landscape pattern. Results indicate that climate change could impose a far greater impact on runoff and nutrient discharge in a peri-urban watershed than landscape pattern change.
Assuntos
Mudança Climática , Hidrologia , Modelos Teóricos , Rios/química , Urbanização , Poluentes Químicos da Água/análise , China , Florestas , Nitrogênio/análise , Fósforo/análise , Qualidade da ÁguaRESUMO
Best management practices (BMPs) are commonly used to reduce sediment loadings. In this study, we modeled the Fort Cobb Reservoir watershed located in southwestern Oklahoma, USA using the Soil and Water Assessment Tool (SWAT) and evaluated the impacts of five agricultural BMP scenarios on surface runoff, sediment yield, and crop yield. The hydrological model, with 43 sub-basins and 15,217 hydrological response units, was calibrated (1991-2000) and validated (2001-2010) against the monthly observations of streamflow, sediment grab samples, and crop-yields. The coefficient of determination (R 2), Nash-Sutcliffe efficiency (NS) and percentage bias (PB) were used to determine model performance with satisfactory values of R 2 (0.64 and 0.79) and NS (0.61 and 0.62) in the calibration and validation period respectively for streamflow. We found that contouring practice reduced surface runoff by more than 18% in both conservation tillage and no-till practices for all crops used in this modeling study. In addition, contour farming with either conservation tillage or no-till practice reduced sediment yield by almost half. Compared to the conservation tillage practice, no-till practice decreased sediment yield by 25.3% and 9.0% for cotton and grain sorghum, respectively. Using wheat as cover crop for grain sorghum generated the lowest runoff followed by its rotation with canola and cotton regardless of contouring. Converting all the crops in the watershed into Bermuda grass resulted in significant reduction in sediment yield (72.5-96.3%) and surface runoff (6.8-38.5%). The model can be used to provide useful information for stakeholders to prioritize ecologically sound and feasible BMPs at fields that are capable of reducing sediment yield while increasing crop yield.
RESUMO
BACKGROUND: Water level fluctuations in endorheic lakes are highly susceptible to even slight changes in climate and land use. Devils Lake (DL) in North Dakota, USA is an endorheic system that has undergone multi-decade flooding driven by changes in regional climate. Flooding mitigation strategies have centered on the release of lake water to a nearby river system through artificial outlets, resulting in legal challenges and environmental concerns related to water quality, downstream flooding, species migration, stakeholder opposition, and transboundary water conflicts between the US and Canada. Despite these drawbacks, running outlets would result in low overspill risks in the next 30 years. METHODS: In this study we evaluated the efficacy of this outlet-based mitigation strategy under scenarios based on the latest IPCC future climate projections. We used the Coupled Model Intercomparison Project CMIP-5 weather patterns from 17 general circulation models (GCMs) obtained under four representative concentration pathways (RCP) scenarios and downscaled to the DL region. Then, we simulated the changes in lake water levels using the soil and water assessment tool based hydrological model of the watershed. We estimated the probability of future flood risks under those scenarios and compared those with previously estimated overspill risks under the CMIP-3 climate. RESULTS: The CMIP-5 ensemble projected a mean annual temperature of 5.78 °C and mean daily precipitation of 1.42 mm/day; both are higher than the existing CMIP-3 future estimates of 4.98 °C and 1.40 mm/day, respectively. The increased precipitation and higher temperature resulted in a significant increase of DL's overspill risks: 24.4-47.1% without release from outlets and 3.5-14.4% even if the outlets are operated at their combined full 17 m3/s capacity. DISCUSSION: The modeled increases in overspill risks indicate a greater frequency of water releases through the artificial outlets. Future risk mitigation management should include providing a flood warning signal to local resource managers, and tasking policy makers to identify additional solution measures such as land use management in the upper watershed to mitigate DL's flooding.
RESUMO
Despite its widespread recognition as a successful model of participatory forest management, the community forestry program in Nepal is often criticized for its protection-oriented emphasis. Recognizing the need for more active timber management, the government of Nepal recently adopted a scientific forest management (SFM) policy in the lowland tropical region. In this study, strength, weakness, opportunity, and threat analytical hierarchical process criteria were employed to understand stakeholder perceptions concerning SFM implementation in Nepal. The overall perception was prioritized in the order of strengths (35%), threats (28%), opportunities (22%), and weaknesses (16%). The study results suggest that there is agreement among stakeholders regarding the need for active management of forests in the tropical lowland region. However, the perceptions of academic researchers and non-government organization professionals differed from those of the other stakeholders in that those two groups were more concerned about potential corruption and uncertainties surrounding policy and legal issues. The findings suggest that the long-term success of SFM may depend on the ability of the government to develop a mechanism that is transparent and capable of ensuring equitable benefit sharing among stakeholders. While the stakeholder perception analysis performed in this study was focused on SFM implementation in Nepal, the results could have implications for other countries that practice the participatory model of forest governance as well.