Rainwater Harvesting, Drought and Floods

RAINWATER HARVESTING

It is a localized system of capturing, collecting, storing and using rainwater flowing in streams, rivers, channels etc.

 

Systems used for Rainwater Harvesting:

  • Construction of check Dams: Also called Micro-Watershed Management, in this, the water from small rivers and streams are diverted and collected into a single water unit.

 

 

  • Construction of ponds, Wells, lakes,   channels, Bawli, Kund (Artificial Tanks).

 

 

  • Roof Top Rainwater Harvesting.

NATIONAL WATER GRID

Grid is a system of transfer from surplus region to deficit region to match demand and supply.

Himalayan rivers have surplus water. Peninsular rivers are deficient of water. Transfer is done by comprehensive and integrated system of artificial dams, reservoirs and canals.

Advantages:

  • Appropriate use of water.
  • Drought & Flood Management.
  • Improved agriculture production & productivity.
  • Inter-regional and regional trade.
  • Employment and income will increase.
  • National integration.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DROUGHT

Drought is an atmospheric condition identified through deficiency of rainfall and moisture. According to the Indian Metrological Department If deficiency of rainfall is 25-50% then it is called Drought and if it is more than 50% then it is called Severe Drought.

Factors

  1. Late onset of monsoon.
  2. Early withdrawal of monsoon.
  3. A long dry spell between two wet spells of monsoon.

Drought Prone Regions Of India

  • These are identified by high fluctuation & failure of rainfall over the years.
  • These are classified into 3 categories.

 

  • Gujarat & Western Rajasthan: Rainfall is low because Aravalis is parallel to South Western Monsoon.

 

(b)       Deccan Plateau: The leeward side of Western Ghats

(c)     Individual Pockets:

 

Economic Effects

Rainfall and Moisture deficiency both are directly related with crop failure and steep fall in agriculture production and productivity.

There is a steep rise in food products; fodder, hoarding and black-marketing of food-grains are common.

As there is a fall in income and employment of farmers. Farmers are forced to undertake distress selling of their land, machines and domestic animals.

 

Social Effects:

Hunger and starvation is common.

People are forced to leave rural villages in search of employment and income; thus the

social fabric of life is fragmented. If drought and efficiency of availability of food is

acute, there is also death through starvation.

Farmers are forced to take loan from moneylenders. They fall into the vicious cycle of

Debt-trop. In case of non-payment, land eviction is common. As a last resort, farmers

commit suicide.

Environmental Effects

Degradation of forest, grasslands, water bodies are common.

Drought is directly connected with desertification.

DROUGHT MANAGEMENT

Drought Prone Area Programme (DPAP) was started in 1974 & 1975 & Desert Development Programme in 1978-79. Both of the programmes emphasized on soil and water conservation to mitigate the side effects of drought strategies includes:

  1. Rain water Harvesting
  2. Expansion of irrigation facilities is through construction of clams, reservoirs & canals.
  3. Expansion of dry land farming which is primarily based on introduction of these inputs:
    • Drought Resistant seeds & crops
    • Drip Immigration & Fountain Immigration

Drip Irrigation: It is a network of directly delivering water and nutrients to the roots of crops. Israel is one of the leading countries in the world to develop this system of irrigation.

Other Techniques:

Soil Conservation

  • Mulching
  • A forestation
  • Grassland Cover

Silviculture means plantations of timber from where the raw materials are provided for rural and cottage industries.

Poultry, Apiculture & Dairy Farming provides additional Employment and income without intensive use of land and water.

 

FLOODS

The rise in water level of rivers and streams and as a consequence submergence of croplands, forests, grasslands and human settlements is described as Flood.

This rise in water level of rivers and streams is caused when the inflow of water exceeds the outflow of water in a given stream or river in a given duration of time.

Factors Associated With Floods

These factors are broadly classified into three:

  1. Climatic Factors
  2. Physiographic Factors
  3. Human Factors.

Climatic Factors: These are:

  1. Extensive catchment area/basin area of river.
  2. Narrow outlet of rivers and streams.
  3. Meandering in the rivers.
  4. Sitting of rivers and streams.
  5. Presence of inland drainage system e.g.: Flood in Western Rajasthan and Gujarat whenever there is a high rainfall.

 

Human Factors: These include the following:

  1. Leakage from dams and canals
  2. Expansion of human settlements towards the belts of rivers and streams.
  3. Deforestation in mountain regions
  4. Sudden opening of the gates of dams and reservoirs.

Effects of Flood

Flood affects the human settlements and even environment. These are broadly classified into the following:

  • Economic effects
  • Social effects
  • Environmental effects

Flood Management

The National Flood Control Programme was started in 1954. It combines both long-term and short term objectives.

Short term- Short term objectives include force-casting and early warning systems to get information on weather changes well in advance.

Short-term activities include.

  1. Evacuation of people
  2. Search and rescue operations
  3. Rehabilitation and relief

Long – Term: Long term objectives includes:

  1. Construction of. Artificial dams, artificial reservoirs, artificial canals to redistribute water from surplus regions to deficit region
  2. Construction of embankments
  3. Strong infrastructure like roads and railways are also part of the long-term objectives. Ultimately, the National Water Grid is considered to be the most important system of infrastructure for controlling and mitigating flood.