by Dr. Mahmood Ahmad, FAO Consultant
1. Characteristics of water
Water is essential, meaning that there is no life without water, no economic production, no environment. The amount of water available is limited by the amount of water that circulates through the atmosphere on an annual basis. All water stems from rainfall, it flows under gravity and if we don't capture it it is lost. The annual water cycle from rainfall to runoff is a complex system where several processes (infiltration, surface runoff, recharge, seepage, re-infiltration, moisture recycling) are interconnected and interdependent with only one direction of flow: downstream. Water is difficult to transport, we transport the produce instead: grains, fruits, vegetable, textile products etc.; commodities that house more than 1,000 times their weight in virtual water - the water required to produce it.
2. Facts on Availability and Use
We need 50 liters of water per day for domestic use with breakdown as follows, 5 liters for drinking, 20 liters for sanitation, 15 liters for bathing, and 10 liters for cooking. We use a whopping figure of 1500 liters for food we eat every day. It is generally a vital and precious resource, but 1 billion rural dwellers still do not have access to clean water (requires efforts to fetch). The importance of fresh water can be judged from the fact that it is only 2.5% of available water, if all the earth’s water were to fit in a gallon jug (4 liters), the available fresh water would be just over 1 tablespoon.
3. The Main Issues
Water is one of the most limiting resources for economic development in the arid environments of the countries around the globe. The pressure exerted by economic and demographic process on the national resource base is a serious concern. In The 20th Century, the population increased by three-fold, where as water demand grew by six-fold, indicating the decline in per capita availability. Water is already being used at maximum capacity in most of the countries implying that the supply is limited but demand is increasing for enhancing irrigation; provision of drinking water; recharging of groundwater supplies and wetlands; and flushing away of municipal and industrial wastes. Therefore, water must be seen in the context of:
· Water for Agriculture;
· Water for People; and
· Water for Nature.
All the three above-mentioned users’ of water contribute significantly in sustained economic growth and meeting food security needs.
However, this quantum increase in demand is bringing water crisis in several regions, most notably in the Middle East and North Africa, but also in an increasingly large number of countries worldwide. Water scarcity varies from region to region; Middle East and South East Asia are very poor in per capita water availability. Per capita availability of water in the North America region is over 10000 cubic meters and on other extreme its only 260 cubic meters in the case of Jordan. The global average was 12000 cubic meters in year 1950 and is projected to decline to 4500 cubic meters in the year 2050. The availability varies considerably over time and space.
The availability of fresh water is not only getting scarce but its quality is also decreasing. Water quality issues of safe drinking water, water logging and salinity, sedimentation, sea water intrusions and waste water use are serious issues. These environmental concerns need to be mainstreamed into water resources development planning and management. In most countries regulation exists to address the problems but their implementation is week. At the same time public awareness campaign on a war footing is needed to address environmental issues related to water use. If we don’t address these issues now, we are simply shifting the problems to our future generation with much higher cost to pay.
Most countries facing erratic rainfall patterns have already developed or are developing many of their economically usable available water sources. Without efficient control and proper water management, most of those countries will find difficult to provide water for life and food. These countries are not using water efficiently, even where water is scarce, the efficiency of the use of irrigation and drinking water is very low. In the case of irrigation subsector, almost half of the water supplied for irrigation never actually gets to the field. This is due to leakage, poor selection of water supply system, low efficiency, and often growing crops that consume too much water. In the case of domestic supply of water, at least one-third of the drinking water for towns and villages leaks out through the network or wasteful misuse, thus wasting billions of dollars each year. We over irrigate when watering our lawns or wash cars. The poor section of population who do not have access to piped water, get less water and pay the most. The case for industrial use is not any different; many industries use and lower the quality of water far in excess of their needs. Here again, one sees defects in recycling, leakage, loss, and inefficient production processes. In brief water is being wasted at all levels of use and we need make productive use of each drop,
4. The Needed Action
We need to save water in our farms, gardens, homes and at all levels, storage, conveyances and distributional and come up with innovative ideas to produce more per drop of water- meaning enhancing water productivity. A list of intervention is proposed and further ideas would be consolidated through our deliberations.
4.1 Upgrade and Develop Available Technologies suitable to local conditions and culture.
Water management–friendly design of surface irrigation systems
Low-cost water harvesting technology
Low-cost water conservation methods in rainfed agriculture
Low-cost pumping and pressurized irrigation systems
Efficient sprinklers to apply water more uniformly
Low-energy, precision application sprinklers to cut evaporation and wind-drift losses
Membrane-covered canals
Adapting drip irrigation to smallholder conditions
Recycling drainage and tail water
Assessment and optimization of irrigation multifunctional
4.2 Use Innovative Technologies
A number of innovative technologies are available that enhance water productivity and save water. The capture of rainwater from roofs provides a valuable source of water for residential or commercial purposes. As a guide, for every 1 inch of rainfall that falls on 1,000 sqf of roof area you can expect to collect approximately 600 gallons of rainwater.
Recent surge in energy cost are making small farming un profitable in many developing countries, a simple and inexpensive human-powered pumps are being used by small-scale farmers in many Asian and African countries. Resource conservation technology such as land leveling, zero tillage and raised bed planting are some of intervention that not only enhances farm productivity but also saves water.
The FAO driven Growing Connection (TGC) programme is supporting schools, communities and other stakeholders in growing fresh nutritious vegetables with the highly flexible and adaptable environments. From villages in Ghana to Nicaragua, to downtown neighborhoods in the USA, participants are using Earth Box that Optimize your produce, maximize yield and promote technology that produces more crops per drop. Simple yet effective, Earth Box system uses 80% less water than an in-ground, drip irrigation system. The Earth Box vastly increases the yield per area over a conventional garden – with less fertilizer & much less water.
No comments:
Post a Comment