Problems Of Development In The Indus Basin Environmental Sciences

Essay add: 15-06-2017, 18:01   /   Views: 3

Although availability of water has been a serious constraint, there are other factors also, which are hampering the growth and development of the sector. Some of the factors are: low productivity of crops, inefficient use of water, degradation of land resources (water logging and salinity), imbalance application of fertilizer, inefficient use of agricultural inputs, ineffective transfer of technology to the farmers, lack of coordination between research and extension, post-harvest losses, marketing infrastructure, etc.

Due to the greatly increased continuous use of Indus water for irrigation (from storage or direct river diversions), there is a considerably distortion in the hydrological balance of the Indus Basin. Seepage losses from irrigation canals, distributaries, minors, and watercourses and deep percolation from the irrigated lands have resulted in a gradual rising of the groundwater table, bringing with it critical problems of water logging and salinity over a vast area. Water logging is widespread throughout Punjab and Sind provinces, where most of the country's food and fiber crops are produced. In the early 1900s, the water table was generally more than 15 meters (m) below the surface throughout the Indus Plain. However, by 1978 (when the Indus Basin Salinity Survey was completed), the water table in 22% of the Indus Basin was within 1.8 m of the surface, and an additional 30% was within 3 m. The condition has get worse since then. There was a comprehensive survey conducted in 1961 calculated that about 40,000 ha of land were being lost per year to agricultural production due to water logging and salinity.

Precision Land Leveling (PLL) is a motorized process of grading and flattening the land to an accurate and regular plane surface at grade or no grade (zero slope) with discrepancy of less than ± 2cm. It is carried out to control irrigation application losses at the farmers’ fields besides other advantages. LASER technology has been proved to be advantageous as it minimizes the cost of irrigation operation, ensures better degree of precision in much lesser time, saves irrigation water, ascertains consistent seed germination, increases fertilizer use efficiency and resultantly enhances crop yields.

Studies on LASER land leveling identifies that:

It cuts back the irrigation application losses up to the extent of 25%

Reduces labor requirements for irrigation by about 35%

By brining the number as well as length of field ditches and dikes to a minimum, it increases the irrigated area by about 2%

It enhances the crop yields by around 20%

Pakistan has promoted the use of LASER technology in irrigated agriculture and is considered to be the pioneer in South Asia for the same.

OFWM Punjab has tested the first laser leveling equipment in 1985. There were 140 LASER land leveling units available with District Governments before devolution, which have been secured through donor assisted projects, respectively. One hundred units were equipped with tractors while 40 units were without tractors. These machines have accurately leveled about 125,000 acres of land. The yearly potential of available LASER equipment was about 25,000 acres per year. The major operational limitation encountered to make sufficient use of this equipment was insufficient availability of O&M funds with the public sector.

There is a drastic alteration in the hydrological balance of the Indus River basin due to the constant expansion of the irrigation system over the past century. Leakage from the system and percolation from irrigated fields caused the water table to get higher, attaining crisis conditions for a significant area. Around 1900 the water table was typically more than sixteen meters below the surface of the Indus Plain. A 1981 study found the water table to be within about three meters of the surface in more than one-half the cropped area in Sindh and more than one-third the area in Punjab. In some areas, the water table is much nearer to the surface. Cropping is fatally affected over a wide area by poor drainage--water logging--and by accumulated salts in the soil.

Officials were conscious of the need for additional expenditure to prevent further worsening of such existing conditions. Emphasis in the 1980s and early 1990s was on rehabilitation and preservation of existing canals and watercourses, on improvements on the farms themselves (including some land leveling to conserve water), and on drainage and salinity in priority areas. Emphasis was also placed on the short-term projects, mainly to improve the operation of the irrigation system in order to lift up yields. Element of the funding would come from stable increases in water use fees; the objective is gradually to raise water charges to cover operation and maintenance costs. Substantial time and money are needed to understand the full potential of the irrigation system and bring it up to modern standards.(detected)

In the beginning of 1990s, irrigation from the Indus River and its tributaries comprised the world's largest adjoining irrigation system, capable of watering over 16 million hectares. The system included three major storage reservoirs and numerous barrages, head works and canals, distribution channels. the canal system exceeds 58,000 kilometers in length and there are a further 1.6 million kilometers of farm and field ditches.

Over the use of Indus waters there were prolonged disputes between India and Pakistan because partition placed portions of the Indus River and its tributaries under India's control. After nine years of dialogue and technological studies, the issue was resolved by the Indus Waters Treaty of 1960. India use of the waters of the main eastern tributaries in its territory--the Ravi, Beas, and Sutlej rivers after a ten year transitional period, the treaty awarded Pakistan received use of the waters of the Indus River and its western tributaries, the Jhelum and Chenab rivers.

Pakistan started an extended and rapid irrigation construction program when the treaty was signed; partly financed by the Indus Basin expansion Fund of US$800 million contributed by various nations, including the US, and administered by the World Bank. Several massive link canals were built to transfer water from western rivers to eastern Punjab to substitute flows in eastern tributaries that India began to redirect in accordance with the terms of the treaty. In 1967 the Mangla Dam, on the Jhelum River, was completed. The dam provided the first major water storage for the Indus irrigation arrangement. The flood control was also contributed by the dam, for regulation of flows for some of the link canals, and to the country's energy supply. At the same time, further construction was undertaken on barrages and canals.

The crucial need in the 1960s and 1970s for crop production for domestic and export markets led to water flows well beyond designed capacities. Completion of the Mangla and Tarbela reservoirs, as well as enhancement in other parts of the system, made superior water flows possible. In addition, the government began installing public tube wells that frequently discharge into upper levels of the system to add to the available water. The higher water flows in parts of the system significantly go beyond design capacities, creating stresses and risks of breaches. However, many farmers suffer because of unreliable water supply and especially those with smallholdings and those on the way to the end of watercourses.

The irrigation system represents a considerable engineering achievement and provides water to the fields that account for ninety percent of agricultural production. Nevertheless, severe issues in the design of the irrigation system avert achieving the highest potential agricultural output.

Article name: Problems Of Development In The Indus Basin Environmental Sciences essay, research paper, dissertation