BEN302 Water Conservation and Management

Manage Water Resources more Effectively

Human beings are made of between 55 to 65% water, which functions to give us structure and sustain all the biochemical processes that keep us alive. Some animals are more susceptible to lack of water – amphibians dry up if the air is too dry or they stay too long out of the water; while other animals have adapted to get enough water only from the foods they consume (terrestrial carnivores). Human beings need between 3 and 3.5 L of water in food and drinks (together) to replace the same quantity lost daily in breathing, transpiration and other body functions.

Plants cannot survive without water. They survive drought periods producing resistant structures specially designed for those periods, be it seeds, or roots, rhizomes or stems that accumulate enough water for the entire dry season. But they will not develop living structures without water.


Lesson Structure

There are 10 lessons in this course:

Introduction to water conservation
Water conservation at home
Water conservation in the workplace
Water management
Water conservation in Primary Production I
Water conservation in Primary Production II
Water conservation in Services industries
Water conservation and Health
Water conservation in other sectors
Water treatment, reuse and recycling

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.
Aims

Explain the importance of water in the world and the reasons for its sustainable conservation and management.
Explain the importance of water conservation and methods to save water at the workplace.
Explain the importance of water conservation and methods to save water at home.
Explain water flow and quality control.
Explain water audits and water management plans.
Explain the importance of water conservation and methods to save water in Horticulture
Explain the importance of water conservation and methods to save water in Agriculture.
Explain the importance of water conservation and methods to save water in the Services Industry.
Explain the importance of water conservation and methods to save water in the Health Industry and allied services.
Explain the importance of water conservation and methods to save water in other occupations.
Explain water sanitation and wastewater treatment methods and the difference with water reuse and recycling.

THE WATER CYCLE

Water is chemically a small molecule made up of Hydrogen and Oxygen. It is a colourless, tasteless and odourless substance that can be liquid, solid (ice) or be present as gas in the air (in this form is called relative humidity).

Water is a universal solvent. Its solvent properties are due to its polarity, with positive (Hydrogen ion H+) and negative electrical charges (hydroxyl ion OH- ) in the molecule. Water dissolves hydrophilic substances such as salts, and repels hydrophobic substances such as fats and oils. Gases can dissolve in water too, such as Oxygen and Carbon dioxide (CO2). This property of water is important as it means that water transport substances from one reservoir to another, contributing with fertilization of land and water, with erosion and with pollutants and particles transport.

Due to its capacity to solve carbonates, water can have buffering properties showing a range of pH values from acidic (pH values lower than 7) to alkalinity (pH higher than 7). Pure water pH is neutral, with a value of 7 in the pH scale. Acid waters can occur naturally, but acid precipitation is not a natural fact. On the contrary, is the result of industrial contamination of the atmosphere. Acid rain is the triggering factor that has contributed to soils degradation and forest loss in several temperate and cold climate countries (US, Canada, Northern and Central Europe). The effects are not direct on the trees, but rather are caused by decreased defence mechanisms against pests and diseases in trees from forests that receive acid rain.

The water cycle or hydrological cycle refers to the changes that occur to water throughout its movement on the Earth’s surface. Surface water present in the Sea, lakes, reservoirs, rivers and on the land evaporates with the Sun’s energy input. Water present in the soil is also evapotranspirated by plants to the atmosphere. Water in the atmosphere condenses into clouds that produce rain (precipitation). Rain replenishes the land (infiltration) and water reservoirs (sea, rivers, lakes, groundwater and soil water) through runoff, thus closing the hydrological cycle.

Both Quantity and Quality of water must be managed!

Water quality is very variable due to natural and anthropogenic (man-made) factors. Water dissolves salts and minerals in its path from mountains to the sea and carries sediments and organic particles (microscopic bacteria, algae, animals or other living organisms). Also there are plants and many animals that live in streams, lakes and dams that feed in other water organisms and that breathe and discharge substances from their bodies (faeces, urine, skin, gases).

Man also produces and discharges into water bodies many substances, organic and non-organic, end products of our activities.

Contaminants can be from:

point sources: wastewater outlets from houses, industries, wastewater treatment plants, etc.
diffuse sources: fertilizers, herbicides, pesticides applied to crops that percolate with irrigation or rain water to underground storages or to surface streams and lakes.

Rainwater also cleans roofs, roads and streets, where car exhausts particles and dust accumulates, thus washing away these contaminants that end up in wastewater treatment plants, or as in most countries of the world, in surface waters.

Contaminants can also pollute underground water. Concerns are high due to chemical contaminants of aquifers, especially in countries or areas where most of the drinking water is obtained from underground sources. Typical contaminants are pesticides and oil derived products.