How to Save Water
There are ever-increasing demands for what is essentially a limited resource - water. This increased demand leads to the construction of more water storage facilities which have a heavy impact on the environment, in such ways as flooding valuable agricultural land or native forests, or by changing the natural pattern of water flow in streams which have been dammed. By minimising the amount of water we use, we can reduce the requirement for additional water storage facilities, and therefore reduce the likelihood of negative impacts on the environment, as well as possibly reducing our production costs.
Most of the following methods of conserving water can be applied equally to crop production or to home garden use:
- By choosing plant species and varieties that best suit the local climate.
- By maintaining a well balanced fertile soil appropriate to the plants selected.
- By watering in the cool of the day.
- By using micro-irrigation systems e.g. trickle systems, where possible. These are much more efficient in their use of water than other irrigation systems.
- By slow, thorough watering: a thorough deep watering once or twice a week will be more effective than watering lightly every day or two.
- By avoiding spraying water on windy days.
- By considering soil type when selecting a watering system: for instance, clay soils hold water well and will distribute it horizontally, so a drip system is suitable, whereas water runs quickly through sandy soil, so a micro-spray would be more suitable as it distributes water over a broader area.
- By reducing excess evaporation: this can be achieved by keeping bare soil covered using mulches or plants. Both organic (e.g. bark, compost, lucerne) and inorganic (e.g. gravel) mulches are excellent for reducing evaporation.
- Compact groundcovers will slow evaporation from the soil but they will use a lot of water themselves Larger plants will shade the soil and limit evaporation but they can make getting water to the soil in the first place rather tricky.
- By using rainwater tanks to gain extra water, particularly for domestic use, and for collecting water from large sheds to water stock. This can reduce the need for installing water mains to some areas to provide water for stock. Troughs can be filled directly from the tank.
Tanks are used to store water which is either collected as run off (e.g. rain collected from roofs), or pumped from natural supplies such as a river. A range of different materials are used to make storage tanks including concrete, metal and fibreglass. Whatever material is used, it should be inert and not contaminate the water. Fresh concrete can cause water to become alkaline, and it must be weathered to remove lime from the cement before use.
Dam and Pond Building
There are two types of dams. One involves building a wall across a water course to collect water as it flows naturally along that course. Permits must be obtained if you intend interfering with the flow of a natural water course. Due consideration should also be given to the impact upon natural wildlife and other sites downstream.
Dams are easier to construct in some soils than others. Dam building is a skill which local contractors in most rural areas have. For a dam to hold water, it needs to be waterproof. Waterproofing is achievable by way of soil type and compaction.
Clays and loams are recommended as these have impermeable qualities. If the existing soil is not suitable then a clay or loam base might be constructed from soil brought onto the site. The thickness will depend upon the size and required strength of the dam to be built. Compaction is best done using a roller, such as those used for road construction - the heavier the better. In some cases where soils are already relatively impermeable, even tractors can be used to compact soil.
Leaking dams can be quickly and easily repaired, and water‑permeable soils, previously considered unsuitable for dam‑making, can now be used with the advent of bentonite as a sealant. This relatively "new" product is being used on existing and new dams with excellent results. The product, along with modern application techniques, is proving a tremendous boon to farmers needing to make dams on unsuitable soils.
The bentonite used for dam sealing is a naturally occurring clay mineral. Dam‑sealing products made from bentonite contain the required additives to ensure maximum swelling and stability when used.
The final bentonite mixture can absorb up to 6 times its mass in water, swelling to 15 times its dry volume, and yielding a water‑impervious, gel‑like substance. If dry bentonite is mixed into any moist soil material it will attract all the available water from the soil, resulting in a bentonite gel binding the soil particles together. Sealing with bentonite is a straight‑forward operation requiring no special skills. However, close attention to the carefully detailed set of instructions usually obtained with the bentonite preparation is essential.
Pool, pond or stream edges can be created with stone, brick, tiles, rock, timber or even plants. Whatever you choose for an edge it must both stabilize the bank (preventing erosion) and create an acceptable visual affect. The edge may be raised above the level of the water, or it may actually merge into the water. The line of the water's edge needs to fit with the style of garden it is found in. Regular, well defined lines are appropriate in more formal gardens, but in a more relaxed, natural style garden, the edge should never be straight or sharply defined. Overhanging rocks and plants enhance a natural affect.
ACS offer a great selection of covers covering such issues as water usage, irrigation and land management, which are listed at the foot of this page.
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