Andhra Pradesh Water Sources

    Andhra Pradesh is blessed with many major rivers, the most important being Godavari, Krishna, Pennar and Vamsadhara. The state, share of dependable flows from all the rivers and streams is estimated at 2746 TMC. And only 1753 TMC has been utilized so far. The total cultivable area of the state is 392 lakh acres and at present 292 lakh acres is being cultivated from all sources.

    After Independence Government have given highest priority for irrigation sector which is the key force behind the agricultural revolution. Many gigantic projects have been taken up in addition to many medium and minor schemes, thus creating a total irrigation potential of 134 lakh acres. The goal is to reach the ultimate IP of 217 lakh acres.

The State's (surface and ground) water resources are estimated to be 108.15 BCM (3820 TMC), out of which about 62.29 BCM (2200 TMC) are currently being utilised for drinking, agriculture, industry and power generation. The per capita annual water resources work out to be slightly more than 1400 Cu. M, and utilisation is about 800 Cu. M. The current percentage withdrawal of available water in Andhra Pradesh is 58%. (Source: Water Conservation Mission – AP Water Vision)

 

Water resources of Andhra Pradesh

The total annual yield of surface water (rivers) is assessed at 2,746 tmc, of which the

major contribution comes from Godavari, Krishna and Pennar rivers. The Godavari

contributes about 1,493 tmc, which constitutes 54% of the total annual yield of surface

water. The replenishable groundwater in the State is assessed at 1,068 tmc. The water

required by 2025 is estimated at 3,814 tmc for irrigation, 122 tmc for drinking, 51 tmc for

industries and 2 tmc for power generation. However, the current utilization of water is

2268 tmc for irrigation, 21 tmc for drinking, 10 tmc for industries and 1 tmc for power

generation.

The average annual rainfall of Andhra Pradesh ranges from 500 mm annually in the

South–West to 1,100 mm in the North-East. Andhra Pradesh is having 27.5 million

hectares of geographical area with gross and net cropped area of 13.2 and 11.5 million

hectares respectively and forests occupying 22.6% of the geographical area and irrigated

area occupy 5.77 million ha (2004-05). The net irrigated area is 3.88 m ha of which

34.7% under canals, 12.3% under tanks and 53% under tube wells and other sources. The

irrigation potential in Andhra Pradesh has been estimated to be 11.3 million ha.

In Andhra Pradesh, the total irrigated area (net) increased from 27.47lakh ha in 1955 to

45.27 lakh ha in 2000. Much of the growth in irrigated area in A.P. since 1985 has come

from tube wells and the area under tanks has decreased. There was no improvement in

irrigated area from 1975 to 2000 under canal system. Rice is the most important irrigated

crop in A.P. In A.P., large parts of new irrigated area are being cropped with rice and the

proportion of rice area that is irrigated is increasing.

The area under food and non-food crops accounts 63 and 37 % respectively of total

cultivated crop area. is under food crops and 37% under non-food crops. The pulses

occupy 1.80, oilseeds 3.04 m ha respectively. In Andhra Pradesh, at present 98.8% of

Sugarcane, 95.8% of Turmeric, 95.2% of Rice, 64.2% of Chillies and 12.7% of Cotton is

irrigated. However, rice consumes 67%, groundnut 8.4% and sugarcane 5.4% of

irrigation water.

The water supplied for domestic and industrial purposes constituted only 0.9% and 0.45%

respectively of the total water utilized in the State in 2001. By 2025, the total assessed

water yield from the surface and groundwater will have to be exploited to the fullest

extent, as the water requirement for the domestic and industrial sectors is estimated to

reach 3% and 1.27% respectively of the State's available resources. By 2025, no

additional demand of water for any of the sectors can be met from the available fresh

water sources of the State. Even to barely meet the projected demands, there will have to

be 100% exploitation of the annual assessed water yield. Given the present population

and the total assessed annual water yield, Andhra Pradesh has a water availability of 1400

m3 per capita per annum, which brings the State into the water scarce category (<1700 m3

per capita per annum is categorized as water scarce).

And by 2020, with the projected increase in the population to 90 million, the water

availability per capita per annum will be 1150 m3, bringing the State closer to the severe

scarce category (<1000 m3 per capita per annum). Thus, in order to sustain further growth

and development, the limited water resources available will have to be utilized effectively

and efficiently.

There are six major soil groups – Red soil (66%); black soil (25%); alluvial clay loam

soil (5%); coastal sands (3%) and problem soils (1%) in the state. Rice is the most

important irrigated crop in A.P. Large new irrigated area are being cropped with rice and

the proportion of rice area that is irrigated is increasing.

To overcome the problems due to frequent failure of monsoon rains and its erratic

distribution in recent years, the Government of Andhra Pradesh has taken up surface lift

irrigation projects on major rivers Godavari and Krishna and their tributaries. The

Government is spending Rs. 500 – 1000 thousand million for providing irrigation to 2.0 –

2.4 million ha additionally through gravity surface canal system and by pumping the

impounded water in Godavari and Krishna rivers and their tributaries to higher elevated

areas (River lift irrigation projects – Bhima, Kalwakurthy, Nettempadu, Devadula, Gutpa,

Alisagar, Dummagudem (Indira sagar and Rajiv sagar) Sripada sagar, Pranahita-Chevella

and Puskaram etc).

Methods of irrigation

The field and horticultural crops are irrigated mostly through surface irrigation by

adopting check basin, border strips, furrow, sprinkler and drip. In Andhra Pradesh under

AP Micro Irrigation Project it is planned to bring 2.5 lakh ha of area under micro

irrigation through drip and sprinkler methods by the end of 2007 with an investment of

Rs. 1200 crores. The micro irrigation which is most efficient water management

technique though recommended for adoption under lift irrigation systems, its adoption is

limited. Further, the scheduling of irrigation through micro-irrigation for different crops

both horticulture and agriculture needs attention for development of technology.

Irrigation efficiency

Irrigation efficiency is defined in terms of the amount of water required for

evapotranspiration (ET) divided by the amount of irrigation water diverted into the

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system. Although the definition of efficiency is not consistent among studies (e.g. it often

includes seepage and percolation [S&P] as well as runoff and transpiration [R&T] as

requirements), the efficiency of rice-based systems is less than 50 percent and lowers in

the wet than in the dry season. Project water use efficiency range from 17-48%. Reasons for

such low efficiencies and remedial measures for improving project water efficiency are

required. Due to various reasons, there is no equity and reliability of water supply under

major irrigation projects in the state. There is considerable scope to improve the irrigation

efficiencies in the irrigation systems of Andhra Pradesh.

Agricultural water management issues in Andhra Pradesh

Major irrigation projects

Major projects of Andhra Pradesh like Nagarjuna Sagar, Sri Ram Sagar, Thungabhadra,

and Srisailam are getting silted every year by loosing more than 5 TMC of water storage.

The problem of silting of reservoirs in medium and minor irrigation projects is also a

common feature in Andhra Pradesh. There is a need to have critical review of catchment

treatment strategies, soil and moisture conservation practices.

Basin wise database on land, water, ecosystems management is meager and it is needed

for proper planning of resources. Need for studies on surface drainage and drainage water

recycling in major irrigation projects for reducing the surface water demand through

irrigation canals. The conjunctive use of ground and surface water in irrigation

commands are not critically analyzed. Further, under the projects the conjunctive use of

rain and surface water is seldom considered in releasing canal water. This practice results

in under utilization of stored water in projects.

The overall objectives are to improve the performance of surface irrigation systems,

where water is supplied to farms from large distribution networks. Attempts are to be

made to determine the effectiveness of these tools in improving irrigation system

performance.

Minor irrigation (Tanks / Lakes)

Andhra Pradesh is having about 80,000 tanks which get filled once in 5-10 years.

Because of this the tanks have become defunct. Lack of sufficient rains (high intensity

rains to generate the run-off) is the main reason for poor filling of the tanks. Inadequate

supply of water from tanks, monocropping with emphasis on rice, salinity and alkalinity

in the command area is the common feature under tanks. The farmers prefer to wait for

the rains and filling of the tank for raising rice instead cultivation of ID crops. In and

around the big cities and towns the tanks / lakes are getting polluted due to release of

feacal, organic and inorganic pollutants. Further, eutrofication is also observed in most of

the lakes and reservoirs.

Due to lack of water in tanks the tube well irrigation under tank commands increased

which created fluoride problem in the villages. The influence of watershed management

works did not result in considerable increase in water table due to continuous withdrawal

of ground water for cultivation. There is a need to study the influence of rainfall, the

watershed works, and their impact on ground water in watersheds (Water Budgeting).

Ground water

The rice cultivation under wells influenced the ground water depletion to a greater extent

and as a result some of the areas have become critical and over exploited. The Central

Ground Water Authority in consultation with the State Ground Water Department,

Government of Andhra Pradesh has declared 80 mandals as critical and 230 mandals as

over-exploited in different districts. Further, due to over-exploitation there is

deterioration in quality of ground water especially fluoride problem in many parts of the

state. These over exploited areas need special attention by which they can be brought

back to sustainability in ground water availability.

In project command areas only 20% of the ground water is utilized where 60% of the

ground water of the state is available. On the other hand, 80% of the ground water is

utilized in non-command areas where only 40% of ground water of the state is available.

The State Government has constituted the "Andhra Pradesh Water, Land and Trees Act

2002 '' to promote water conservation, tree cover and check the exploitation and use of

ground and surface water for protection and conservation of water sources, land and

environment and matters connected therewith or incidental thereto.

Water quality

The quality of a river is maintained by its flow, minimum silt and indicated by its

ecological balance and biodiversity, including fisheries. Increased population,

industrialization, agriculture intensification and other activities like aquaculture have

contributed to increased waste discharge into the surface water bodies especially in

rivers.

Surface water

Surface water, i.e., water in rivers, streams and tanks, has been contaminated with

sewerage and other solid wastes from urban and rural habitations and industrial pollution.

The National River Conservation Plan (NRCP) has selected Bhadrachalam, Manchiryal,

Rajahmundry, and Ramagundam form comprehensive treatment of pollution. The

possibility of recycling domestic waste into fertilizers poses a tremendous potential and

must be actively piloted.

Groundwater

Due to frequent poor and erratic rainfall, there is a pressure on groundwater utilization.

Indiscriminate tapping of groundwater in the State by too much drilling and construction

of deep tube wells and bore wells, followed by unregulated pumping of wells have

resulted in over exploitation and depletion of groundwater resources in certain areas. The

trend of the depth to water level from 1998-2002 indicates an average fall of 2.97 M in

the State. Tremendous increase in wells from 0.8 million to 2.2 millions in 22 years, with

corresponding increase in area irrigated from 1.0 million hectares to 2.6 million hectares

has resulted in the exploitation of 56% of annual ground water resources of the State.

Groundwater is an important source of drinking water but is polluted because of the

waste generated in the industrial, agriculture and domestic sectors. According to a report

of the State Ground Water Department and on data generated over the last 10 yeas in

Telangana region, fluoride concentration is high in ground water in Nalgonda and

Karimnagar districts In Coastal Andhra salt water intrusion was found . In Anantapur

district of Rayalaseema region high fluoride concentration is found in groundwater. It has

reached endemic proportions in Nalgonda, RangaReddy, Kurnool, Karimnagar and

Prakasam districts.

In rivers like Musi, Krishna, Godavari and their tributaries the faecal / toxic pollutants

contaminate the water and result water pollution. The river Musi is the most

contaminated one due to release of urban untreated human and animal wastes into the

river. The water pollution is observed on both sides of the river upto 100 Km length. Use

of this water for cultivation of crops includes para grass, rice and vegetables. The

intensity of contamination decreases as the distance from Hyderabad increases. The

different concentrations of wastewater influence differently on the biodiversity and

human activities.

Due to decrease in river water flows that empty into sea in the coastal area resulting in

ingression of salinity in land thereby the salinity of inland soil and ground water is

increasing in some parts of the coastal Andhra.