Modeling channel management impacts on river migration: a case study of Woodson bridge state recreation area,Sacramento river,California, USA

Understanding how hydraulic factors control alluvial river meander migration can help resource managers evaluate the long-term effects of floodplain management and bank stabilization measures. Using a numerical model based on the mechanics of flow and sediment transport in curved river channels, we predict 50 years of channel migration and suggest the planning and ecological implications of that migration for a 6.4-km reach (river miles 218–222) of the Sacramento River near the Woodson Bridge State Recreation Area, California, USA. Using four different channel management scenarios, our channel migration simulations suggest that: (1) channel stabilization alters the future channel planform locally and downstream from the stabilization; (2) rock revetment currently on the bank upstream from the Woodson Bridge recreation area causes more erosion of the channel bank at the recreation area than if the revetment were not present; (3) relocating the channel to the west and allowing subsequent unconstrained river migration relieves the erosion pressure in the Woodson Bridge area; (4) the subsequent migration reworks (erodes along one river bank and replaces new floodplain along the other) 26.5 ha of land; and (5) the river will rework between 8.5 and 48.5 ha of land in the study reach (over the course of 50 years), depending on the bank stabilization plan used. The reworking of floodplain lands is an important riparian ecosystem function that maintains habitat heterogeneity, an essential factor for the long-term survival of several threatened and endangered animal species in the Sacramento River area.     

Evaluation of soil erosion risk using Analytic Network Process and GIS: A case study from Spanish mountain olive plantations

The study presents an approach that combined objective information such as sampling or experimental data with subjective information such as expert opinions. This combined approach was based on the Analytic Network Process method. It was applied to evaluate soil erosion risk and overcomes one of the drawbacks of USLE/RUSLE soil erosion models, namely that they do not consider interactions among soil erosion factors. Another advantage of this method is that it can be used if there are insufficient experimental data. The lack of experimental data can be compensated for through the use of expert evaluations. As an example of the proposed approach, the risk of soil erosion was evaluated in olive groves in Southern Spain, showing the potential of the ANP method for modelling a complex physical process like soil erosion.     

A management strategy to reduce bacterial pollution in shellfish areas: A case study

The problem of bacterial pollution in shellfishing areas is not uncommon in the coastal regions of the United States. Bacterial contamination from man's activities can effectively reduce our natural shellfish resource areas by forcing their closure because of high potential risk of diseases being spread by shellfish harvested in these areas. Tillamook Bay, a relatively small, enclosed drainage basin of nonurban character, presents an excellent study area for observing this problem. The high population density of animals, raised on a relatively small floodplain area, represents one of the major sources of pollution in the bay. This paper summarizes the history of the agencies involved with the problem and presents the current approach to alleviate bacterial pollution in the bay without unduly penalizing other industries in the Tillamook basin. The paper also presents some of the legal aspects of reducing water pollution in shellfish harvesting areas and the jurisdiction of federal agencies in these matters. Finally, recommendations are given to reduce bacterial output by the major source categories in the basin, and criteria for bay closure to shellfish harvest are developed to protect the public from bacterially contaminated shellfish.     

Exploring management strategies for community-based forests using multi-agent systems: A case study in Palawan, Philippines

This paper describes the experiences and lessons learned in applying a multi-agent systems (MAS) model to study the dynamics and complex interactions among stakeholders in the management of community-based forests. The MAS model is developed using the companion modelling (ComMod) approach, which allows for a collaborative development of the model between the stakeholders and researchers. This approach involves the development and application of role-playing games (RPGs) and computer simulation as learning tools and to validate the model. Inferences are drawn from the learning and negotiation processes that the stakeholders and researchers underwent in the collaborative development of the MAS model. These processes ultimately led to the development of a collaborative resource management plan. The approach and the MAS model were applied to a case study involving a community-based forest managed by three villages in the island of Palawan, Philippines.     

A process integration approach to industrial water conservation: a case study for a Chinese steel plant

A systematic approach to optimizing water network has traditionally been utilized to exam and plan water conservation in industrial processes. In the present case study, water-pinch technology was used to analyze and optimize the water network of a steel plant near China's Zhangjiakou city. A system design was developed and a limiting constraint (Cl(-) concentration) was identified based on investigations of water quality then the minimum freshwater and wastewater targets were determined without considering water losses. The analysis was then extended by calculating the additional input of freshwater required to balance the actual water losses. A nearest-neighbor algorithm (NNA) was used to distribute the freshwater and recycled water among each of the plant's operations. The results showed that with some reconstruction of the water network, the flow rates of freshwater and wastewater could be decreased by 57.5% and 81.9%, respectively.     

Particulates pollution management and economic analysis of small rural enterprises in mountain areas: A case study of Wenquan town in China

At present, many rural enterprises in China's mountainous areas are developing rapidly, and due to poor planning and improper management, in an uncontrolled manner. These small enterprises are making atmospheric pollution far more serious and more difficult to control than before. Thus, as is the case with most developing countries, China is facing the challenge of managing the increased environmental pollution that is accompanying its economic development. This paper examines the case of cement dust pollution in the town of Wenquan in Sichuan province in order to determine how to adjust the relationship between development of rural enterprises and atmospheric environmental pollution in mountainous areas. Using the single objective linear programming method, and based on the principle of overall optimization, an optimal control plan for different pollution sources was worked out and an economic assessment on reclamation of cement dust was completed. According to our analysis, after implementation of this plan for four years, two months, the concentrations of suspended particles in Wenquan will achieve the requirement of the national third-order ambient air quality standard; the current serious dust pollution will be completely controlled; and the reclamation of cement dust will totally compensate for the cost of dust control and will result in 92,000 yuan of pure profit per year. At that time, the economy and environment will be in harmony.