|
|
|
Mapping gully erosion patterns in foothills of lower Shiwaliks
S S Kukal
Department of Soils
Punjab Agricultural University, Ludhiana-141 004, India
Email: sskukal@rediffmail.com
Bhoop Singh
Director/Scientist F, DST, New Delhi
Introduction
Soil erosion by water is a serious problem of land degradation in foothills of lower Shiwaliks. Gully erosion is the most spectacular form of erosion as the damage caused by it is relatively permanent. Nearly 20% of the total land in the region is under gullies (Kukal and Sur, 1992). Gully erosion is most prevalent type of water erosion as it dissects the fields, impedes the tillage operations, damages agricultural, residential and recreational land and causes environmental pollution. The damage caused by the gullies is significant compared to other forms of erosion as the sedimentation production form the gullies is to the tune of 147% of that from other types of erosion (Grissinger and Murphy, 1989). Further the gully network in the region is responsible for the generation of higher amount of runoff despite of the presence of sufficient vegetation cover. Various factors controlling gully growth are catchment characteristics viz. area (Burkard and Kostaschuk, 1997), slope steepness (Kukal et al., 1991), slope shape (Meyer and Martinez-Casasnovas, 1999), gully dimension parameters, surface runoff, precipitation, soil moisture and piping (Stocking, 1980).
The foothills of lower Shiwaliks, covering an area of 2.14 m ha, falls in the state of Punjab, Haryana, Himachal Pradesh and Jammu and Kashmir and because of peculiar geological formations represent the most fragile eco-system of the Himalayan ranges. These are exposed to greater biotic pressure due to their proximity to plains. Ecological degradation in Shiwaliks is the outcome of continued over-exploitation and mismanagement of soil resources through deforestation, over-grazing and clearance of land for agricultural purposes disregard to slope and topography of the land. Efforts are being made by different agencies to control gullies in the region but with little success. The present study is being carried out under the auspices of Department of Science and Technology, New Delhi to examine the pattern and growth of gullies in relation to catchment characteristics in foothills of lower Shiwaliks.
Materials and Methods
A survey was conducted during September 2001 to January 2002 in different catchments in the region to study the performance of various gully erosion control structures installed by different agencies and data collected on various parameters viz., catchment area, slope, vegetation, land use etc. Information on these parameters was collected in about 10 catchments representing different soil and land characteristics. The physical damage was categorized as (i) partial- the structure was not completely destroyed but part of the runoff water was flowing from the side of the structure either due to physical damage to the structure or due to the erosion of the gully bank and (ii) complete when the structure to such an extent that little runoff was being intercepted.
Gully erosion mapping was carried out in four catchments of Saleran in district Nawanshahar through ground surveys so as to find out the extent and distribution of different ordered gullies in the area in the form of gully density, gully texture etc. The catchment characteristics viz. shape, size, relief and vegetation density were recorded.
|
|
|