Return flow

Last updated

Return flow is surface and subsurface water that leaves the field following application of irrigation water. [1] While irrigation return flows are point sources, in the United States they are expressly exempted from discharge permit requirements under the Clean Water Act. [2]

Return flows generally return to the irrigation centre after a period of about three to four weeks; due to this, the farmers usually need to pour bleach into the water to clean it of any organisms that have entered the stream. If this is not taken care of, diseases such as typhoid or cholera could enter the irrigation and pose a risk of epidemic disease to surrounding towns and cities.

The return flows in irrigation is nearly 50% of the water supplied in silty clay soil type in tropical countries. The salinity of the return flow water increases with decrease in % of return flow quantity. Rest of the water supplied to irrigation evaporates to atmosphere due to evapotranspiration.

When ground water is extracted for irrigation and other uses, most of the return flows seep back into the ground instead of joining the nearby surface stream. When ground water is used in excess of recharge from rainfall/precipitation, the quality of groundwater deteriorates over a period of time and becomes unfit for irrigation use.

Related Research Articles

Aquifer Underground layer of water-bearing permeable rock

An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials. Groundwater from aquifers can be extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include aquitard, which is a bed of low permeability along an aquifer, and aquiclude, which is a solid, impermeable area underlying or overlying an aquifer, the pressure of which could create a confined aquifer.

Stormwater water that originates during precipitation events and snow/ice melt

Stormwater, also spelled storm water, is water that originates from rain, including snow and ice melt. Stormwater can soak into the soil (infiltrate), be stored on the land surface in ponds and puddles, evaporate, or contribute to surface runoff. Most runoff is conveyed directly to nearby streams, rivers, or other water bodies without treatment.

Grey water Type of wastewater generated in households without toilet wastewater

Grey water or sullage refers to wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from toilets. Sources of grey water include sinks, showers, baths, washing machines or dishwashers. As grey water contains fewer pathogens than domestic wastewater, it is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses.

Groundwater Water located beneath the ground surface

Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology.

Water resources law

Water resources law is the field of law dealing with the ownership, control, and use of water as a resource. It is most closely related to property law, and is distinct from laws governing water quality.

Rainwater harvesting Accumulation of rainwater for reuse

Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit, aquifer, or a reservoir with percolation, so that it seeps down and restores the ground water. Dew and fog can also be collected with nets or other tools. Rainwater harvesting differs from stormwater harvesting as the runoff is collected from roofs, rather than creeks, drains, roads, or any other land surfaces. Its uses include watering gardens, livestock, irrigation, domestic use with proper treatment, and domestic heating. The harvested water can also be committed to longer-term storage or groundwater recharge.

Prior appropriation water rights is the legal doctrine that the first person to take a quantity of water from a water source for "beneficial use" has the right to continue to use that quantity of water for that purpose.

Water right in water law refers to the right of a user to use water from a water source, e.g., a river, stream, pond or source of groundwater. In areas with plentiful water and few users, such systems are generally not complicated or contentious. In other areas, especially arid areas where irrigation is practiced, such systems are often the source of conflict, both legal and physical. Some systems treat surface water and ground water in the same manner, while others use different principles for each.

Nonpoint source pollution Pollution resulting from multiple sources

Nonpoint source (NPS) pollution is pollution resulting from many diffuse sources, in direct contrast to point source pollution which results from a single source. Nonpoint source pollution generally results from land runoff, precipitation, atmospheric deposition, drainage, seepage, or hydrological modification where tracing pollution back to a single source is difficult.

Streamflow, or channel runoff, is the flow of water in streams, rivers, and other channels, and is a major element of the water cycle. It is one component of the runoff of water from the land to waterbodies, the other component being surface runoff. Water flowing in channels comes from surface runoff from adjacent hillslopes, from groundwater flow out of the ground, and from water discharged from pipes. The discharge of water flowing in a channel is measured using stream gauges or can be estimated by the Manning equation. The record of flow over time is called a hydrograph. Flooding occurs when the volume of water exceeds the capacity of the channel.

Krishna Water Disputes Tribunal Indian tribunal

Government of India constituted a common tribunal on 10 April 1969 to adjudicate the river water utilization disputes among the river basin states of Krishna and Godavari rivers under the provisions of Interstate River Water Disputes Act – 1956. The common tribunal was headed by Sri RS Bachawat as its chairman with Sri DM Bhandari and Sri DM Sen as its members. Krishna river basin states Maharashtra, Karnataka and old Andhra Pradesh insisted on the quicker verdict as it had become more expedient for the construction of irrigation projects in Krishna basin. So the proceedings of Krishna Water Disputes Tribunal (KWDT) were taken up first separately and its final verdict was submitted to GoI on 27 May 1976.

Water politics Politics affected by the availability of water and water resources

Water politics, sometimes called hydropolitics, is politics affected by the availability of water and water resources, a necessity for all life forms and human development.

Perennial stream type of river

A perennial stream or perennial river is a stream or river (channel) which has constant stream throughout the year through parts of its stream bed during years of normal rainfall. In the absence of irregular, prolonged, or extreme drought, a perennial stream is a watercourse, or segment, element, or emerging body of water which continually delivers groundwater. For example, an artificial disruption of stream, variability in flow or stream selection associated with the activity in hydropower installations, shall not affect the measurement. Perennial streams do not consist of stagnant water for the wetlands, reservoirs, and ponds that occur all the period. All other streams, or portions thereof, should be considered seasonal rivers or lakes. The stream can cycle from broken to perpetual through multiple iterations, to intermittent through its mechanism.

Surface water

Surface water is water located on top of the Earth's surface such as rivers, creeks, and wetlands. This may also be referred to as blue water. The vast majority is produced by precipitation and water runoff from nearby areas. As the climate warms in the spring, snowmelt runs off towards nearby streams and rivers contributing towards a large portion of our drinking water. Levels of surface water lessen as a result of evaporation as well as water moving into the ground becoming ground-water. Alongside being used for drinking water, surface water is also used for irrigation, wastewater treatment, livestock, industrial uses, hydropower, and recreation. It is recorded by the Environmental Protection Agency (EPA), that approximately 68 percent of water provided to communities comes from surface water. For USGS water-use reports, surface water is considered freshwater when it contains less than 1,000 milligrams per liter (mg/L) of dissolved solids.

Water resources in India Information on precipitation, surface and groundwater storage and hydropower potential in India

Water resources in India includes information on precipitation, surface and groundwater storage and hydropower potential. India experiences an average precipitation of 1,170 millimetres (46 in) per year, or about 4,000 cubic kilometres (960 cu mi) of rains annually or about 1,720 cubic metres (61,000 cu ft) of fresh water per person every year. India accounts for 18% of the world population and about 4% of the world’s water resources. One of the solutions to solve the country’s water woes is to create Indian Rivers Inter-link.c Some 80 percent of its area experiences rains of 750 millimetres (30 in) or more a year. However, this rain is not uniform in time or geography. Most of the rains occur during its monsoon seasons, with the north east and north receiving far more rains than India's west and south. Other than rains, the melting of snow over the Himalayas after winter season feeds the northern rivers to varying degrees. The southern rivers, however experience more flow variability over the year. For the Himalayan basin, this leads to flooding in some months and water scarcity in others. Despite extensive river system, safe clean drinking water as well as irrigation water supplies for sustainable agriculture are in shortage across India, in part because it has, as yet, harnessed a small fraction of its available and recoverable surface water resource. India harnessed 761 cubic kilometres (183 cu mi) (20 percent) of its water resources in 2010, part of which came from unsustainable use of groundwater. Of the water it withdrew from its rivers and groundwater wells, India dedicated about 688 cubic kilometres (165 cu mi) to irrigation, 56 cubic kilometres (13 cu mi) to municipal and drinking water applications and 17 cubic kilometres (4.1 cu mi) to industry.

Water resources Sources of water that are potentially useful

Water resources are natural resources of water that are potentially useful. 97% of the water on the Earth is salt water and only three percent is fresh water; slightly over two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of fresh water include surface water, under river flow, groundwater and frozen water. Artificial sources of fresh water can include treated wastewater and desalinated seawater.

Water pollution in India Water pollution in India is mainly due to untreated wastewater discharge into rivers

Water pollution is a major environmental issue in India. The largest source of water pollution in India is untreated sewage. Other sources of pollution include agricultural runoff and unregulated small-scale industry. Most rivers, lakes and surface water in India are polluted due to industries, untreated sewage and solid wastes.

Godavari Water Disputes Tribunal

Government of India (GoI) constituted a common tribunal on 10 April 1969 to solve the river water utilization disputes about the river basin states of Godavari and Krishna rivers under the provisions of Interstate River Water Disputes Act – 1956. The common tribunal was headed by Sri RS Bachawat as its chairman with Sri DM Bhandari and Sri DM Sen as its members. Godavari river basin spreads through the states of Telangana (TS), Maharashtra (MR), Orissa, old Madhya Pradesh {later bifurcated into present Madhya Pradesh (MP) and Chhattisgarh}, Karnataka (K) and Andhra Pradesh (AP). Krishna river basin states Maharashtra, Karnataka and Andhra Pradesh insisted on the quicker verdict as it had become more expedient for the construction of irrigation projects in Krishna basin. So the of Godavari Water Disputes Tribunal (GWDT) could not proceed till the Krishna Water Disputes Tribunal final verdict was submitted to GoI on 27 May 1976.

Micro-irrigation

Micro-irrigation, also called localized irrigation, low volume irrigation, low-flow irrigation, or trickle irrigation, is an irrigation method with lower pressure and flow than a traditional sprinkler system. Low volume irrigation is used in agriculture for row crops, orchards, and vineyards. It is also used in horticulture in wholesale nurseries, in landscaping for civic, commercial, and private landscapes and gardens, and in the science and practice of restoration ecology and environmental remediation.

Fresh water naturally occurring water with low amounts of dissolved salts

Fresh water is any naturally occurring water containing low concentrations of dissolved salts and other total dissolved solids. Though the term specifically excludes seawater and brackish water, it does include non-salty mineral-rich waters such as chalybeate springs. Fresh water may include water in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rainfall, rivers, streams, and groundwater contained in underground aquifers.

References

  1. Andrew Keller; Jack Keller; David Seckler. "Integrated Water Resource Systems: Theory and Policy Implications" (PDF). Retrieved 31 January 2020.
  2. United States. Clean Water Act, section 502(14), 33 U.S.C.   § 1362.