Long-throated flumes and broad-crested weirs

Vital for water management are structures that can measure the flow in a wide variety of channels. Chapter 1 introduces the long-throated flume and the broad-crested weir; it explains why this family of structures can meet the boundary conditions and hydraulic demands of most measuring sites.Chapter 2 records the history of these structures. It describes how the hydraulic theory of flumes and weirs, and their design, developed separately. The chapter concludes by reporting recent attempts to develop a generally valid theory for any long-throated flume or broad-crested weir in any channel. The remainder of the thesis explains the steps taken to develop a procedure that yields the hydraulic dimensions and rating table of the appropriate weir or flume. The major steps cover the hydraulic theory of flow through control sections of different shapes and dimensions, the theory and procedure of estimating the head loss required for modular flow, the boundary conditions of the channel, and the demands placed on the structure regarding the range and accuracy of its flow measurements

Quantifying the sustainability of agriculture

The rural sustainability index is a scientifically based tool to quantify the performance of agriculture. The sustainability of crop production is quantified from three perspectives; people, planet and profit. Within each perspective, one condition was selected that must be met to warrant agriculture. These are: No hazardous work should be used within the crop production chain; agricultural crops should not be grown on land allocated to nature by national law or regulations and, when a GM-crop is present or is introduced in a region, it should not harm development opportunities of other farmers. If these excluding conditions are met, the sustainability of agriculture is assessed through five performance indicators on school attendance, water use and consumption, fertilizer use, pesticide use, and farm income. For each of the five indicators, critical values and target values have been given that limit the transition range between non-sustainable and sustainable production. The five indicators are combined into a sustainability index. The index aims at improving the socio-economic position of farmers while protecting the environment