The Return of Large Dams to the Development Agenda: A Post-Development Critique

Large dams are making a comeback. Large dams reflect an outdated development paradigm narrowly focused on economic growth through modernization. This article employs a post-development lens to highlight three biases of the narrow development perspective that underlies large dams. First, it views rivers, and nature more generally, as an unrealized source of economic growth and an input to production. Second, it is blind to distributional impacts and is resultantly inequitable: the benefits of large dams are concentrated in the hands of the wealthy, while conditions for the poor do not improve and often worsen. Third, it disempowers those supposedly being developed by de-politicizing the development decisions to pursue large dam projects. Each of these biases is illustrated by reference to the Mekong River Basin’s experience with large dam development. It is concerning, therefore, that large dams seem to be making a resurgence in Asia, Africa and South America, and are once again receiving World Bank support. This article serves as a reminder of why large dams do not deliver equitable development and faded from the development agenda at the turn of the century

Atmosphere: the formation of sulfate particles

Attempts to explain how new particles are nucleated. The volatily of (NH 4) 2SO 4 was measured in terms of the equilibrium ammonia vapour pressures above the solid samples. Results are in accord with a simple theoretical model which suggests how the nucleation occur

The African Pollen Database (APD) and tracing environmental change: State of the Art

International audienc

A difference expansion technique to analyse the advection/dispersion/sorption equation for phosphorous

A finite difference technique for numerical analysis of the partial differential equation for advection and dispersion with sorption is presented in detail. The sorption term is non-linear and it is difficult to simulate the breakthrough curves when the rate of change of concentration is large. A general technique is used which expands the derivatives in terms of increasing orders of finite differences. This has become possible with the advent of symbolic manipulation. It is possible to expand to any order and, importantly, separate out the terms for each order. Details are presented, together with methods for exploring the convergence and stability as well as adjusting the time and spatial differencing to lower or minimise· the error

Chloride movement in a de-watered saline soil profile

Surface ripping affected the downward movement of water and solutes within a saline dewatered duplex soil profile near Kellerberrin. Prior to ripping, 63% of the total rainfall ended up as runoff and there was little evidence from tensiometric measurements and soil solution samples of significant downward flows of water below a depth of 0.3m. Following ripping to a depth of 0.2m to break a near surface hard layer: runoff was reduced to around 13%; there was some change in soil matrix potential; some leaching of the surface soil occurred; and several preferred water fluxes were intercepted at a depth of 1.5m. These intercepted fluxes were recorded shortly after (<1hr) high intensity rainfall greater than 20mm, suggesting post ripping flow through macropores. The initial chloride storage in the profile was 162t ha-1, approximately 5t ha-1 chloride was leached during the field study (3%). The main leaching mechanism before ripping was runoff (0.5t ha-1). After ripping, flow through macropores and mesopores accounted for 0.5t ha-1 , runoff 0.09t ha-1 with the rest redistributed through the soil matrix