Gopal Nakarmi

Gaining forests but losing ground: A GIS evaluation in a Himalayan watershed

GIS overlay techniques were used to provide a quantitative historic documentation of deforestation and land-use dynamics in the Middle Mountains of Nepal between 1947 and 1990. Deforestation was most critical in the 1960s, but active afforestation programs in the 1980s have reversed the process. In spite of these trends, the degradation problem is more complex. The GIS evaluation showed that 86% of the recently afforested land is now under pine plantations located primarily at lower elevations and moderately steep slopes. In contrast, rainfed agricultural expansion is most pronounced on acidic soils and steeper, upper elevation sites, suggesting marginalization of agriculture. Agricultural expansion coupled with major losses of grazing land to pine forests are the key processes pointing towards major animal feed deficits. An alternative animal feed source is suggested through GIS using a topographically based microclimatic classification to generate a tree-planting map where the optimum ecological conditions for selective native fodder tree species are identified.

Potential Solutions to Water Scarcity in the Rural Watersheds of Nepal's Middle Mountains

Abstract Water scarcity is a major issue in rural watersheds in the Middle Mountains of Nepal and in the entire Hindu Kush–Himalaya region. Dense population and heavy dependence on irrigated agriculture place immense pressure on available water resources, which have a distinct seasonality. New forms of management based on traditional and scientific knowledge must be introduced to solve problems of water supply, water demand, and water quality in these watersheds. A related article in the Research section of this issue, Water: A Scarce Resource in Rural Watersheds of Nepals Middle Mountains, by Juerg Merz et al, further explores the problem of water availability in Nepal. Ed.

Human interactions in soil and geomorphic processes in Nepal: the role of soil fertility in degradation and rehabilitation processes

Abstract A GIS approach was used in the determination of soil fertility status in the Jhikhu Khola watershed. The watershed was stratified by topography, climate, soil type and land use using GIS overlay techniques. A (2 × 2 × 2 × 4) factorial approach served as the sampling framework to produce single and combined nutrient deficiency GIS maps. Soil acidity, phosphorus availability and lack of base cations were identified as the key soil fertility issues, with forests having the poorest overall soil nutrient status, followed by rangeland, rainfed agriculture and irrigated agriculture. Nutrient budget calculations revealed significant annual deficits in phosphorus for maizerotations but only minor deficits for rice rotations. The effect of inherited biophysical conditions on nutrient deficits were analyzed statistically and displayed using the GIS overlay method. Poor fertility and annual deficits were linked to erosion and sedimentation by documenting annual erosion losses from rainfed agriculture and degraded areas. Over a 7 year period, typical erosion from maize rotations in rainfed agriculture averaged 19 t/ha annually, while erosion from degraded sites were 75–100 percent higher. Significantly different sediment rating curves were obtained from two micro-watersheds, one with 14 percent and the other 25 percent degraded areas. Annual sediment contributions to the micro-watersheds confirmed that degraded sites increase the suspended sediment load, particularly under lower stream flow conditions. The discharge-sediment regression line was significantly higher during the pre-monsoon period than during the monsoon season. GIS tools were found to be useful in all parts of the analysis.

Assessing Renewable Water Resources and Water Use in Angola

“Nature” is one of the culturally most loaded concepts. It is one of the central concepts for human understanding and structuring of the surroundings (Glacken, 1967). The concept of nature is deeply embedded in our understanding of the world, so deep that we seldom reflect its central role in our thinking. With impulses from symbol theory (Elias, 1991), environmental history (Berntsen, 1994; Nash, 1982) and social sciences (Berger and Luckmann, 1987), this article examines nature, not as a physical reality, but as a symbol of ideas, norms and values in society. “Nature” is understood and interpreted in a historical, social and cultural context.

Prevention, Degradation and Rehabilitation: A New Dilemma in Himalayan Watersheds

Watersheds in the Middle Mountains of Nepal are some of the most intensively used drainage basins in the world and degradation in the form of erosion, soil fertility decline, water quality deterioration and declining water supplies is widespread. If degradation processes are recognised in the early stages, rehabilitation is relatively easy, but rehabilitation of sites in an advanced state of degradation is a formidable challenge. Degraded sites, which cover less than 7% of the watershed area, are responsible for more than 1/3 of the annual sediment budget in the Jhikhu Khola watershed. With a combination of grasses and native nitrogen fixing fodder trees, it proved possible to establish good vegetation cover within a 2-year period. However, rehabilitating soil nutrients is painfully slow and differences in parent material have a great impact on biomass production and restoring nutrients. More attention needs to be directed towards sediment and nutrient budget calculations as a means of recognising the early stages of degradation, and thus facilitating rehabilitation early in the degradation cycle.

Water Management Issues in Middle Mountain Catchments of the Nepal Himalayas: The Downstream Perspective

Middle mountain catchments in the Hindu Kush-Himalayan region are the heavily populated and mainly rainfed headwaters of many smaller, but not less important rivers, and the tributaries of the larger North-South rivers draining the mountain system. The catchments are in a fragile and vulnerable region from the perspective of water scarcity, flooding and soil erosion. It is these catchments which caused the theory of the ”Himalayan Environmental Degradation” (Eckholm, 1976).