Hydrosphere – Water & Wetlands
Introduction
Planet earth- rightly termed as blue planet because of enormous quantity of water enveloping the earth, is unique in harbouring life on earth as we know today. The term hydrosphere represents this part of the earth.
For millions of years, the intricate balance between hydrosphere and atmosphere has resulted in the observed global pattern of seasons, cycle of snow and rainfall, summers and winters, droughts and floods. This has consequences on life in a myriad mystifying ways. Over a period of last two hundred years, man has been exercising enormous influence on climate primarily through his activity. The carbon dioxide content in the atmosphere is now steadily increasing. There is a forty percent decline in arctic ice thickness in recent history. It is estimated that the global mean sea level has already increased by ten to twenty centimeters.
The frequency of floods and droughts has increased enormously. The increase of global surface temperature will result in alteration of hydrological cycle changing rainfall, runoff and consequent frequency of floods.
Available water resources in India
Of the total precipitation, only forty seven percent is available for any practical purpose. The rest goes in evapo-transpiration, runoff, and percolation losses.
The surface water forms a mere 17 percent and ground water is about 10 percent. Yet, ground water is used for fifty percent of the irrigated agriculture!! Eighty percent of rural and fifty percent of urban population depend on ground water for their domestic needs. In a global warming context, the increase in surface temperature alters regimes of groundwater recharge as well. This has serious implications for a country like India where two fifths of Indian agriculture out put is contributed from areas irrigated by ground water.
Three-fourth of the total annual rain fall happens between just four months between June and September. The spatial and temporal variation in the quantity and distribution of water in various parts of the country creates and maintains the extraordinary diverse biological diversity of the country. Nearly 40 percent of the biodiversity lives in water and the remaining life forms survive supported by water.
Aquatic ecosystems cover a variety of habitats in the form of inland, coastal and marine systems encompassing rivers, ponds, lakes, reservoirs, marshes, estuaries, lagoons, mangroves, marine habitats and so on. Life originated in water and no life can exist without water.
[the following three boxes can go to appropriate places]
Distribution of water on EarthThe world's total water supply is about 1,386 million cubic kilometers of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Thus, surface-water sources (such as rivers) only constitute about 93,100 cubic kilometers, which is about 1/700th of one percent of total water. Nevertheless ,rivers are the source of most of the water people use.
Hydrological cycle
Succession of stages through which water passes from the atmosphere to the earth and returns to the atmosphere: evaporation from the land or sea or inland water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.
Water resources of India(billion cubic meter)
Annual precipitation 4000
Available water resources 1869
Utilizable 1122
Surface water (storage and diversion) 690
Groundwater (replenishable) 432
Present utilization 605
(Surface water 63%, groundwater 37%)
Irrigation 501
Domestic 30
Industry, energy and other uses 74
Project 1.
Mapping of Wetlands and study the variations in biodiversity.
Introduction:
Wetlands include rivers, lakes, marshes, swamps and similar areas. Wetlands are one among the most endangered ecosystems of the world. It is estimated that 2050, a significant extent of aquatic biodiversity and habitat will be lost, largely due to human influences. Recent studies have concluded that serious loss of wetlands has taken place in many states of India. We would therefore require detailed plan for an inventory mapping on conservation planning.
Objectives:
- To map wetlands and riverine eco systems to know the extend of area and its changes.
- To study the common life forms supported by the wetlands
- To understand ecological importance of the wetlands for the provision of ecosystem goods and services.
Materials required:
Survey of India Map 1:50000 scale, cadastral map and satellite image of known scale (if possible) for different scale you have to calculate according to the scale of map used
Methodology:
Obtain 1:50000 Survey of India toposheet or cadastral map or satellite image from Google Earth for your area of interest. Take a transparent tracing paper overlay it on the map and trace water bodies, swamps marshes, and rivers and streams also write down the place names, village / town on the tracing paper. Give the numbers to each of the traced water bodies and marshes. Estimate the area of the wetland / water body using a graph paper. Calculate the total area on the earth surface based on the scale of the map used. Tabulate the data which you have collected. Study the biodiversity associated with the wetlands using any of the method explained in biosphere section such as transects, surveys and counts and tabulate the species you encounter. Discuss the results with village communities as many of the water bodies; swamps would have changes structure, shape and content over the recent years. In some cases many water bodies would gone and some additional water bodies would also have come up.
Analysis and Interpretation:
Analyze the data for the variation of the size in wetlands, marshes for given area around radius of 1-2 km for select villages. Discuss the human use pattern and the economic significance of the water bodies for agriculture, domestic and livestock use. Look for differences in biotic communities such as fish, birds and plants. Discuss the emerging information from the tabulated data, with the other children, teachers and villagers in detail.
Follow up:
Children can give this map they have made and the information they collected to the village office or any people in need to sensitize the importance of their resource that can help in improvement sometime even in their livelihood. They can go for an awareness campaign for the conservation of the local wetlands giving valid scientific reason came out of their study.
Project 2
Rain water harvesting for water security
Introduction:
As the water scarcity is getting serious one should be thinking of harvesting of water for consumptive uses. Children can take up project in estimating potential of rainwater harvesting in different locations. Though some part of the rain fall is lost due to evaporation and percolation, the net available water can be calculated by using approximation
Objective:
- To estimate the harvestable rain water in different localities.
- Compare the potential of rain water harvesting to supplement available water and support water security
Methodology:
Select a house with clean roof for the purpose
Measure the plinth area of the building as ‘A’ sq.m.
Find the rain fall in your area and express it as in ‘R’.meters
Assume the collection efficiency of the roof as ‘C’(usually 50 to 90%)
Compute total volume of water ‘Q’ available annually from the roof
Q= A x R x C = ‘X’ m3 = X x1000 L
If water is used to supplement existing need, the storage tank capacity can be 10% of Q m3 available (Q x0.1).
Make a simple rain gauge, install it and measure the rainfall regularly
Device a method to measure the water level in the storage tank without contaminating it and record it daily as volume of water in the morning and evening (height X area = volume).
Check the water quality at regular design intervals H2S strip test bottles. If it reveals contamination disinfect the water in the tank [Record the volume, measure the dosage of disinfectant and apply it, allow for prescribed time before using it]
Compare and contrast the harvestable rain water for different land also.
Follow up:
This information and the project results can be utilized in the rain water storage tanks. Discuss with communities for eliciting their opinions in making rain water storage.
Project 3
Rendering water safe for drinking using simple methods.
Introduction:
We often use expensive and external energy dependent processes for rendering water safe for drinking. There are alternative, simpler methods to do the same job.
Objective:
Rendering the water bacteriologically safe for drinking.
Possible Methods:
.
- Exposing waer in a glass bottle to sunlight for a length of time
- Use of copper sheet, silver or brass vessel
Methodology:
- Take a one litre glass bottle
Fill it 3/4th with water close with lid, shake it well to dissolve maximum amount of oxygen in it. Fill the bottle and close the lid tightly.
Keep it in bright sunlight away from the reach of animals and children for few hours.
- Keep the water in a brass vessel for few hours before use
Or put a sheet of clear copper sheet or some silver coins/ chain in a container for a length of time.
Test the sample water quality to ensure presence of bacteria using H2S strip test.
Subject it to either method A or B for different length of time and test the water quality.
Determine the minimum time of exposure required to achieve disinfection.
In method B change the surface area of copper sheet, number of coins etc and express it as effective area for the given volume of water.
Social relevance : Often simpler, effective solution are ignored a forgotten resulting in reliance on external sources and methods. These simple elegant methods can improve the driving water quality and hence health significantly
Follow-up action:
Children can do a simple survey to find out the safety of drinking water as in practice in the area and the measures adopted locally for ensuring the safety.
[Children may test many other traditional methods such as use of Vetiver.]
Methodology for
Testing bacteriological quality of water using H2S strip test
Take the H2S strip bottle and open lid.
Fill it fully with water to be tested (without touching water with hands)
Close the lid
Keep it is a dark place for 24 hrs
Observe the colours of water in the bottle
If it has turned black if reveals bacteriological contamination. If it is light brown it shows absence of bacteria.
Empty the bottle after the test and sterilize the bottle.
Project 4.
Treatment of grey water using reeds and plants for recycling
Introduction.
Bulk of water used in household will emerge as grey water and contain some minerals, organic waste materials dissolved and suspended in it. When this is allowed to flow out this will join the sewage and bacteriologically contaminated, resulting in a sewage stream. It is possible to intercept this grey water, at the household level, treat it so that it can be recycled for garden washing and flushing purposes.
Objective
To evolve an easily implementable method of treating grey water at household level
Methodology
Select a unit such as house or school for study.
Asses the nature of grey water generated in a day and classify as kitchen, bath and others.
Collect samples and observe the contents for sediments (settleable solids) and turbidity (suspended solids)
Setup and experiment to contain such examples and introduce water plants or/ and reeds whose roots are in water. Observe the effect on quality of water after certain time.
Observe weather there is improvement in water quality with time and how much time is required for improvement.
Compare the effect of different plants.
A pebble bed can support reeds. Fill it with grey water, let it establish if self and repeat the experiment.
Study if there is an improvement in water quality. If there is, then what should be the size and shape of the system.
Project 5
Aquatic weeds
Introduction
Weeds are species which spread fast in an area and most of them are alien and thus termed as Invasive Alien Species. We can come across some free floating species in the aquatic ecosystems, especially ponds and lakes such as water hyacinth (eichhornia salvinia. Some other native species which invade the wetlands and spread extensively in the wetlands are also described as weeds, for example Ipomoea and some grasses. Water hyacinth, although a common weed, is known to invade the pond/lake and cover large extent making the area less usable by many birds and fishes.
Objectives
1) To understand the variety and abundance of the weeds in the wetlands in the locality
2) To know their use/ non-use, practice and potential
3) To identify their impact on the wetlands.
Materials required
1) Map of the area
2) Books on plants and birds with pictures
3) Weighing balance
4) Data sheets, notebook and pen/pencil
Methods:
1) Conduct a survey of ponds and lakes in the locality. Travel around and visit these areas. Mark the name of each pond or lake on a map (rough map or more accurate one may be got from the administrative authorities of the locality such as the Village Panchayat, township, city, or prepare a map as suggested in a project on mapping of wetlands). Visit each pond or lake periodically once or twice a month and conduct observations.
2) Data to be collected on:
a) Enumeration of the plant species by noting the names, Common and scientific names by asking some people and by referring to books or taking help from experts in the school or in the locality.
b) Extent of area covered: Make a copy of the map of the pond or lake on a graph sheet. Mark the areas with different types of the plants in a rough way with the weeds covering the squares of the area. Squares can be marked with thick, medium or less growth of plants. Then, count the number of squares having the above types of vegetation. From this we can calculate the percentage of area covered by different grades of plants, i.e. high, medium and low densities
c) Abundance of the weeds: take four sticks of 25cm and tie them to form a square. Put this on the surface of water with plants. Take out the plants freely those which are floating and other rooted plants by cutting above the soil. Remove water by keeping for some time and get the weight using a weighing balance. Take a few such samples from different locations and get the average wet weight.
d) Enumerate the birds of each area and mark the areas used by them on the grid map. Similarly other biota such as insects also can be marked. Varieties and quantity of fish from each of these wetlands also can be documented by sampling or by enquiring with the local people.
Observations
e) Comparison of the ponds and lakes: Tabulate the results for each wetland and compare among them about the present situation. This will bring out the use of these habitats by different species of birds and by comparing different types of areas we can assess the impact of the weeds on the wetland and their biota.
f) Assess the changes over the years from the results of enquiries with the people.
Follow up activities
1) Cleaning up of some wetlands keeping the desired level of natural vegetation with the help of the schoolmates and the local people as a voluntary activity.
2) Use these resources for other purposes such as manure or for making some handicrafts items.
3) Regular monitoring of these wetlands by the children and, later the teachers can take it up with other children in the coming years.
4) Generate awareness among the local people for reducing any menace to the wetlands by keeping them clean.
Project 6
Wetlands and Bird life
Introduction
Wetlands form the waterlogged wealth and birds form one of the important components of this ecosystem. In India, we have about 1270 species of birds of which 325 are wetland dependent, partly or fully. Many of the wetland birds come to India for feeding during the winter and go back to their breeding grounds in the colder or temperate countries. Some species breed in the high altitude wetlands in our country and come down to the lower regions in the country.
Objectives
1) To understand what kinds of birds are using different wetlands and the changes in different months of the year.
2) To document the changes in the population with reference to the weather changes in the particular region.
Materials required
1) Map of the area
2) Books on birds with pictures.
3) Binoculars for observing the birds from a distance
4) Data sheets, notebook and pen/pencil
Methods
1) Conduct a field Survey and mapping of the local wetlands such as rivers, ponds, lakes in the area. Mark the name of each pond or lake on a map that can be acquired from the administrative authorities of the locality such as the Village Panchayat, township, city, or prepare a map as suggested in a project on mapping of wetlands. Visit each pond or lake periodically once or twice a month and conduct observations.