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The water on earth is always moving and changing its state from one form to another, for example from liquid to vapor form. This process of continuous movement and changing the state is known as water cycle and hence during the formation of water cycle several process take place. All these processes have an important role to play where some have significant and some have less significant role to play. Here we will have a look at five main components of water cycle along with their description are (USGS Home, Jan 2012):

1. Evaporation

The first important component of water cycle is evaporation. In a water cycle, the water is continuously changing state and moving. Hence, evaporation helps the water to change from one state to another, during which water moves from the liquid state back into the water cycle as atmospheric water vapor.  As we know, about 70 % of Earth’s surface is covered by oceans because of which large-scale evaporation happens here and as a result most of the water that evaporates from the oceans falls back into the oceans as precipitation out of which only 10% of the water evaporated from the oceans is transported over land and falls as precipitation.

2. Sublimation

Sublimation is a process where the snow or ice changes its form and at times this happens without the snow melting into water and is considered to be a very common way for snow to disappear in specific climates. Sublimation happens in certain weather conditions and not always, especially when there is low relative humidity and dry winds or at higher altitudes, where the air pressure is less than at lower altitudes. In such areas this process holds a lot of importance for the water cycle and therefore is considered to be another important component that has an impact on water cycle.

3. Condensation

Another important component of water cycle is condensation where the water vapor in the air changes its form and turns into water hence this component holds a lot of value for water cycle as it helps in cloud formation. The process of condensation helps the water to come back to the surface of earth and as a result be part of the water cycle.

4. Precipitation

For water cycle, it is important for the water from clouds, rain, snow or hail to move back into its original state and vice versa and this is where Precipitation comes into action as it is the water released from clouds in the form of rain, snow or hail. Therefore, Precipitation is another important component of water cycle as it helps get the atmospheric water to earth.

5. Infiltration

Infiltration is the process where the water in the form of rain or snow falls on the surface of ground and gradually seeps into the soils and moves to combine with a stream or some water body thus completing the water cycle and hence Infiltration is also considered to be an important component of a water cycle.

Answer 1 (b)

Water balance is the process that keeps track of water volumes that enter or leave any three dimensional space over a specific period of time. It is extremely important to define the spatial and temporary boundaries of water balance so that the water balance can be calculated correctly. There are certain elements that are required for a perfect water balance. These elements are as follows (Burt Charles M., 99):

1. Storage at Beginning of Period

The water that comes from various entities is stored at the beginning keeping in mind the entire year and is thus averaged. However, it is not possible to assess for the water logging which can differ from time to time. Therefore, in areas where there is a lot of water logging, it is required to assess water balance season wise as well as year wise.

2. Inflows

This is the water that comes in from various entities like streams, rivers, groundwater, rain water etc.

3. Outflows

This is the water that flows out of the storage to other entities.

4. Change in storage
5. Storage at end of period

The diagram below shows the elements of water balance (Ridder de and Boonstra J.).

Source: www.water.gov.au

Equation for water Balance

The simplest form of equation for water balance is:

Inflow = Outflow + Change in Storage

The water balance equation can be accessed for any volume or any period of time.

In areas where there is rain water storage, water balance can be calculated as:

Rainfall – RiverOutflow = Evapotranspiration

Answer 2 (a)

In modern urban life, while there is a need for clean and clear water everywhere, there are increased level of pollutants in abundance.  Let us look at how we can ensure that the lakes are protected from the pollutants and other impacts which are after impacts of urbanization. Some of the immediate benefits that can be thought of are (Faber Rudolf, December 2006):

• Lesser pollutants and nutrients entering the lakes which can be done by managing stormwater at source before it drains into the lake.
• The requirement for rehabilitation and maintenance of downstream waterway will go down.
• A lot more improved visual and recreational function of the urban landscape with an integrated approach to management of open space.

One of the key factors to be considered while designing for lake protection is Shoreline Development as this is a valuable piece of lank that can be bought at huge cost. However, with time this very piece of land is inhabited with greatest density of homes within 500 feet of the lake. With this shoreline becoming dense, the pollutants are also in abundance. Thus all the more reason to protect the shorelines so that the lakes are not polluted. To ensure a pollutant free lake, it is required to protect the lake in four zones as shown in the figure below (Faber Rudolf, December 2006):

These four zones are:

Shoreline

The shoreline begins as the point where the mean high water mark meets the land. Given the importance of the shoreline to lake ecology and screening, it is essential that this zone be retained in a natural state, with minimal disturbance of native vegetation. A common approach to manage the shoreline is to require shoreline permits for any activity that modifies, alters, clears or otherwise disturbs the natural shoreline.

Shoreline Buffer

When natural shoreline buffers are maintained, they protect the integrity of the shoreline, provide habitat for wildlife and fish, reduce the likelihood of erosion, and help to reduce runoff and pollutant loads.

Shore land Protection Area

The shoreland protection area extends beyond the shoreline buffer and is primarily intended to regulate the geometry and nature of development on lots adjacent to a lake. In a way, the shoreland protection area is a special overlay zone for residential development, and includes various setbacks, impervious cover limits and forest conservation requirements.

Watershed

Establishing shoreline buffer zones may not always be enough to protect a lake from the impact of land development, particularly if it is sensitive to increased phosphorus inputs. If significant land development is expected in a lake watershed, the LPO must be designed to create a fourth management zone that encompasses the watershed as a whole (Faber Rudolf, December 2006).

Answer 2 (b)

The total water supplied to Australia has an impact of toilet water being flushed and this has more impact when there are restrictions for the usage of water. Though the toilets in Australia are water efficient there is still a lot more that can be done, for example there are dual flush toilets available in Australia that are highly efficient. These toilets come in different capacities. The other type of water efficient toilets are integrated with hand basin which are being currently used in numerous hotel toilets. An area that needs to be explored now is Urine Separating Toilets. These toilets are a huge success in Europe. These toilets have two bowls within a single pan and allows for allows very low flush volumes for the reduced or urine flush compared to the full flush. These toilets if used can lower the consumption of flush from 4L to 1 L. It is not very difficult to implement, it is just that it requires a lot of behavior changes from people. Some examples are that both men and women need to sit and urinate so that the urine gets separated. Another important change that people need to make is not to flush napkins into the same basin. These toilets are also available in different volumes and are very common in Sweden. In order for Implementation in Australia, apart from behavior changes, the architectural changes and infrastructure also needs to be kept in mind. And more importantly the support for Municipal Corporation is required. At the same time, there might be some initial technical hiccups that need to be looked at (Schlunke Anna, Lewis James and Fane Simon, 2008).

Answer 3 (a)

Residual flood risk can be described as a risk that remains after the protection system has been put into place. It covers the accepted risk, the unknown risk and the risk due to false judgment or inadequate counter measures and decisions.

There are certain steps that need to be considered to mitigate the risk. Some of these are (Burt Charles M., 99):

1. All developments in flood risk areas should be tested for any risks. As a result there is a need to build structures that are flood resistant. There have to be specific routed identified so that water can be diverted in case there are floods and also measures are taken to lower the impact to a great extent.
2. Another important step is to raise the floor levels above the regular ground level. Engineering excellence can be used to elevate the floors so that flood water does not enter the buildings.
3. Another step can be flood resistant construction where care is taken to design the internal layout as well which is not limited to living area but towards storage and parking as well. The design has to be such so that the flood water does not enter the building thus damaging the structure and if by chance the water does enter, the design has to be such that the recovery is fast as well.

Answer 3 (b)

The three main components that determine the flood risk are Flood Hazard, Vulnerability and Exposure (Burt Charles M., 99).

Flood hazard can be defined as an event that is threatening in nature which also includes the probability of intervals at which it would be happening and the magnitude of occurrence. There are certain ways of preventing the same and has been discussed further.

Exposure is the habitation, human beings that are present at the location where the flood has come. In case there is some prior information or climate reports, these areas can be vacated.

Vulnerability is the lack of resistance to damaging or destructive forces i.e no measures are being taken to save the self.

Flood risk can be mathematically calculated as the combination of above mentioned components and hence to manage these it is important to have some mechanism in place that aims to reduce the likelihood  or the impact of floods. Hence it is important to ensure the following in order to manage the risk of floods. These can be classified as follows (Burt Charles M., 99):

1. It is important to prevent damages caused by floods and this can be done by avoiding construction of houses and industries in areas that are vulnerable to floods. Even if there is a remote possibility of flood, construction needs to be avoided. In such areas, more forests can be developed.
2. Secondly, it is important to take measures that help in protection against the floods and if possible take measures that can help either to ensure that floods do not happen in a particular locality or the impact is reduced to a great extent.
3. Third, it should be imperative to educate the masses about the risks associated with flood and how to prepare oneself and protect if such an emergency happens.

References

[1] Faber Rudolf, December 2006. “Flood Risk Analysis: Residual Risks and Uncertainties in an Austrian Context”. Department of Water, Atmosphere and Environment Institute of Water Management, Hydrology and Hydraulic Engineering. Vienna.

[2] Summary of Water Cycle, January 2012. Water Science for Schools. USGS.

[3] Cappiella Karen and Schueler Tom. “Crafting a Lake Protection Ordinance”.

Urban Lake Management.

[4] Janeiro Rio de, 23-24 September 2009. “A water account for Australia”. Water Accounting Workshop.

[5] Ridder de and Boonstra J. “Analysis of Water Balances”. International Institute for Land Reclamation and Improvement.

[6] Engel, S., and J. L. Pederson. 1998. “The Construction, Aesthetics, and Effects of Lakeshore Development: A Review”. Wisconsin Department of Natural Resources.

[7] Heimberger, M., Euler, D., and J. Barr. 1983. “The Impact of Cottage Development on Common Loon Reproductive Success in Central Ontario.” WilsonBulletin 95: 431-439.

[8] Schlunke Anna, Lewis James and Fane Simon, 2008. “Analysis of Australian Opportunities For More Water-Efficient Toilets.” The Australian Government Department of the Environment, Water, Heritage and the Arts. Institute for Sustainable Futures.

[9] Burt Charles M., 99. “Irrigation Water Balance Fundamentals.” Conference on Benchmarking Irrigation System Performance.

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