Irrigation Aishvarya Srivastsava Iim Lucknow

Design an Irrigation system

that is

that is

that can

self sustainable

replicable

cater to large areas

• Allows future generations to have the same opportunities to benefit from our land as we do – Continues to generate agricultural products at reasonable costs into the future – Ensures that environment is itself maintained so that it can sustain the communities that depend upon it – Does not degrade the quality of land, water and other natural resources that contribute to both agricultural production and environmental quality

How? • It extracts only the amount of water that can be replenished through recharge • It applies water to crops efficiently • It minimizes downstream environmental damage

• For river systems • We propose to extract only a sustainable amount of water from the river systems that ensures that river health is maintained • We should take less than 50% of the median flows of the river

• For groundwater systems • Our extraction should not exceed replacement, so the resource is maintained in the long term

• Use tools to measure river health • Based on the biological outcomes based around aquatic invertebrates, fish, algae, floodplain vegetation and waterbirds • They give more information than on the concentrations of various chemical substances

Objective

• Apply water to crops efficiently • Minimize losses during delivery to site & application to crops • Apply only the amount of water that crop needs

Problems

• In open channels • Around 15-25% of water is lost to seepage and evaporation • On farm losses of some 24% are common with seepage and evaporation • only 36% of the water that leaves storage finds its way to the plant

Solution

• In lighter soils, use lining or pipe water to achieve significant savings •Use soil moisture sensors and computer driven systems to ensure water is only supplied when it is needed

• Use micro-irrigation tools – tickle, drip, spray • More than 90% efficient • Can use relatively saline water • Programmable

• Use Irrigation scheduling • Monitor moisture availability • • • •

Crop stage of growth and vigor Air temperature and wind speed Rainfall or irrigation water applied Soil moisture

• Calculations needed • Daily crop water use or evapo-transpiration • Soil water balances and water available to plants

Objective

Solution

• Reduce downstream impacts • Manage drainage to minimize waterlogging and salinisation

• Intercept the salty water and dispose of it to evaporating basins away from the river, and to salty aquifers • Treat our irrigation system as a closed system that must manage its salt within their boundaries rather than accept a subsidy from others by dumping it to the environment • Water reuse • Reuse irrigation water prior to discharge • Use municipal waste water for irrigation

• Use irrigation benchmarking system • To analyse the range of water use efficiencies in each commodity and each area

• Increase irrigation efficiency • Control seepage loss • Reduce evaporation in fields • Schedule irrigation based on soil moisture and plant needs • Don’t over-fertilize crops • Control weeds that compete for water • Time planting to take greatest advantage of natural precipitation

• Select appropriate land to irrigate

• We need to select the most appropriate soils to irrigate • These will be the soils that have the least waterlogging risk and salt hazard • Use airborne remote sensing to identify salt reservoirs and pathways in the landscape, so we can avoid applying water to such areas • Use pumped pipe systems to deliver water to the most appropriate areas rather than just flood areas that are downslope of a distribution channel

• as the salinity of soil or water increases, more water should be applied to push salt down below the root zone