This document discusses various techniques for water harvesting and conservation. It introduces water harvesting as the collection of rainwater where it falls through techniques like catchment systems and runoff collection. Key principles are outlined such as using rainwater effectively, avoiding runoff, and reducing evaporation and drainage. Specific techniques are then described in detail, including micro and macro catchments, contour farming, terracing, stone lines, retention ditches, bunds, cover crops, drip irrigation and more. Design considerations for small structures like micro catchments and ponds are also covered.

1. WATER RESOURCE MANAGEMENT
MODULE 5 – WATER
HARVESTING AND
CONSERVATION

2. INTRODUCTION – WATER HARVESTING
• IT IS THE ACTIVITY OF DIRECT COLLECTION OF RAIN WATER
• IT MAINLY MEANS CAPTURING RAIN WATER WHERE IT FALLS AND CAPTURE RUNOFF
FROM CATCHMENT STREAMS
• HIS COLLECTED WATER COULD BE STORED FOR LATER USE AND RECHARGE INTO
GROUND WATER AGAIN.
• THIS INCLUDES ALL MEASURE THAT INDUCE, COLLECT, STORE AND CONSERVE
RAINWATER

3. PRINCIPALS OF WATER HARVESTING
• IN DECIDING WHICH TECHNIQUE TO USE TO MAKE MORE EFFICIENT USE OF AVAILABLE
WATER IT IS IMPORTANT TO CONSIDER HOW CROPS RECEIVE OR LOOSE WATER
• CROPS RECEIVE WATER THROUGH RAINFALL, IRRIGATION AND STORED SOIL WATER.
• THEY LOOSE THROUGH RUNOFF, EVAPORATION AND DRAINAGE.
• SOME OF THE KEY PRINCIPALS ARE :
1. USE RAINWATER EFFECTIVELY : AS RAINFALL IS UNEVENLY DISTRIBUTED AND MANY
AREAS HAVE DROUGHTS WHERE CROPS CANNOT GET READY WATER

4. PRINCIPALS OF WATER HARVESTING
IN SUCH AREAS TECHNIQUE SUCH AS EXTERNAL CATCHMENT OR ROOFTOP
COLLECTION CAN INCREASE THE AVAILABILITY OF WATER
2. MAKE EFFECTIVE USE OF SOIL WATER RESERVE: THE SOIL STORES WATER
FROM RAINFALL WHICH IN TURN PROVIDES RESERVE THAT IS AVAILABLE. THE
AMOUNT OF AVAILABILITY OF WATER DEPENDS UPON SOIL TYPE AND ROOFING
SYSTEM.
3. TAKE MEASURE TO AVOID RUNOFF: RUNOFF IS WHERE WATER IS NOT
ABSORBED TO SOIL AND RUNS ACROSS SURFACE. STRUCTURES SUCH AS
COUTURE SCHEME, TERRACING, PITS AND BUND CAN REDUCE RUNOFF.
4. AVOID WASTING WATER THROUGH EVAPORATION : WATER THAT EVAPORATED
DIRECTLY FROM SOIL IS WASTEFUL AS IT IS NOT USED BY PLANTS. IT IS
DESIRABLE TO MAINTAIN FULL GROUND COVER FOR AS MUCH TIME POSSIBLE.
USE OF DRIP IRRIGATION AND IRRIGATION IN EVENING WILL ALSO REDUCE
EVOPERATION.

5. PRINCIPALS OF WATER HARVESTING
5. REDUCE WATER LEVEL THROUGH DRAINAGES : WHEN WATER DRAINS FROM
SOIL, NOT ONLY WATER BUT NUTRIENTS SUCH AS NITROGEN ARE ALSO WASTED. THIS
PROBLEM EXISTS ON SANDY AND CLAYEY SOIL. ADDITION OF ORGANIC MATTER
WILL REDUCE THE DRAINAGE AS SOIL CAN HOLD MORE WATER.
6. PLANNING OF IRRIGATION : IRRIGATION IS ONE WAY OF SUPPLEMENTING WATER
FROM RAINFALL AND SOIL RESERVE, BUT IT WASTES LARGE AMOUNT OF WATER IF
NOT HANDLED CAREFULLY. IRRIGATION MUST BE DONE ONLY WHEN NECESSARY.
DRIP IRRIGATION IS MOST SUITABLE AND IN WATER SCARCE AREAS IRRIGATION CAN
BE DONE AT THE TIME OF GERMINATION AND FRUIT SET.

6. WATER HARVESTING TECHNIQUES
• VARIOUS TECHNIQUES WILL BE SUITABLE FOR VARIOUS CONDITIONS.
• A TECHNIQUE USEFUL IN ONE AREA MAY NOT BE IN OTHER .
• IT IMPORTANT TO NOTE THAT THESE TECHNIQUES ARE LOCALLY DEVELOPED OR
ADOPTED WITH SPECIFIC CONDITIONS.
• TYPES OF WATER HARVESTING METHODS :
1. MICRO CATCHMENT
2. MACRO CATCHMENT

7. WATER HARVESTING TECHNIQUES
• MICRO CATCHMENT : THIS SYSTEM COLLECTS SURFACE RUNOFF AS A SHEET FLOW
OVER A SHORT DISTANCE FROM A SMALL CATCHMENT AREAAROUND 1000 SQ M.
• RUNOFF WATER IS USUALLY APPLIED TO AGRICULTURAL AREA WHERE IT IS STORED IN
ROOT ZONE THAT CAN BE USED DIRECTLY BY THE PLANTS AND CAN ALSO BE STORED
IN SMALL RESERVOIR AROUND PLANT FOR LATER USE.
• MACRO CATCHMENT: THEY ARE CHARACTERISED HAVING RUNOFF WATER
COLLECTION RELATIVELY FROM A LARGER CATCHMENT AREA. RUNOFF CAPTURE IS
LOWER THAN MICRO CATCHMENT.

8.  CONTOUR FARMING: CONTOUR CULTIVATION (CONTOUR FARMING, CONTOUR
PLOUGHING, OR CONTOUR BUNDING) IS A SUSTAINABLE WAY
OF FARMING WHERE FARMERS PLANT CROPS ACROSS OR PERPENDICULAR TO SLOPES TO
FOLLOW THE CONTOURS OF A SLOPE OF A FIELD. THIS ARRANGEMENT OF PLANTS BREAKS
UP THE FLOW OF WATER AND MAKES IT HARDER FOR SOIL EROSION TO OCCUR.
1. CONTOUR PLOUGHING : THE FARMING PRACTICE OF PLOUGHING AND/OR PLANTING
ACROSS A SLOPE FOLLOWING ITS ELEVATION CONTOUR LINES.
• THESE CONTOUR LINES CREATE A WATER BREAK WHICH REDUCES THE FORMATION OF RILLS
AND GULLIES DURING TIMES OF HEAVY WATER RUN-OFF; WHICH IS A MAJOR CAUSE OF SOIL
EROSION.
• WATER BREAK ALSO ALLOWS MORE TIME FOR THE WATER TO SETTLE INTO THE SOIL. IN
CONTOUR PLOUGHING, THE RUTS MADE BY THE PLOUGH RUN PERPENDICULAR RATHER
THAN PARALLEL TO THE SLOPES, GENERALLY RESULTING IN FURROWS THAT CURVE
AROUND THE LAND AND ARE LEVEL. THIS METHOD IS ALSO KNOWN FOR PREVENTING
TILLAGE EROSION.

9. 2. CONTOUR FURROW : CONTOUR FURROWS AND RIDGES ARE CONSTRUCTED ALONG
CONTOUR LINES. STRIP CULTIVATION OR CROPPING IS THE GROWING OF A CULTIVATED CROP
(AS CORN) IN STRIPS ALTERNATING WITH STRIPS OF A SOD-FORMING CROP (AS HAY)
ARRANGED TO FOLLOW AN APPROXIMATE CONTOUR OF THE LAND AND MINIMIZE EROSION.
 TERRACE FARMING : TERRACE FARMING IS A METHOD OF FARMING THAT CONSISTS OF
DIFFERENT "STEPS" OR TERRACES THAT WERE DEVELOPED IN VARIOUS PLACES AROUND
THE WORLD.
• THIS METHOD OF FARMING USES "STEPS" THAT ARE BUILT INTO THE SIDE OF
A MOUNTAIN OR HILL. ON EACH LEVEL, VARIOUS CROPS ARE PLANTED. WHEN IT RAINS,
INSTEAD OF WASHING AWAY ALL OF THE NUTRIENTS IN THE SOIL, THE NUTRIENTS ARE
CARRIED DOWN TO THE NEXT LEVEL. ADDITIONALLY, THESE STEPS PREVENT A FREE
FLOWING AVALANCHE OF WATER THAT WOULD TAKE PLANTS WITH IT AND DESTROY ALL OF
THE CROPS ON THE HILLSIDE. THIS SYSTEM ALSO ALLOWED THEM TO BUILD AQUEDUCTS,
WHICH CARRIED WATER TO EACH LEVEL.

10.  STONE LINES : IT SLOW DOWN RUNOFF, INCREASE WATER INFILTRATION, AND SEDIMENT IS
CAPTURED BEHIND THESE SEMI-PERMEABLE BARRIERS, IMPROVING PRODUCTION. A
PERENNIAL GRASS CAN SUPPLEMENT THE LINES WHERE STONE IS SCARCE. SUITED TO LOW
SLOPES, HIGH RUNOFF AND HAND LABOUR. THIS TECHNIQUE IS READILY ADOPTED BY
RESOURCE-POOR FARMERS AND CAN LEAD TO A HARVEST EVEN IN YEARS WITH LOW AND
ERRATIC RAINFALL.
RETENTION DITCHES : WORK ON A SIMILAR PRINCIPLE TO CONTOUR FURROWS BUT ON A
LARGER SCALE. THEY ARE LARGE DITCHES, DESIGNED TO CATCH AND RETAIN ALL
INCOMING RUN-OFF AND HOLD IT UNTIL IT INFILTRATES INTO THE GROUND, INCREASING
THE SUPPLY OF WATER TO CROPS PLANTED IN THE DITCH AND REDUCING SOIL EROSION

11.  SEMI-CIRCULAR BUNDS : ARE USED TO REHABILITATE DEGRADED, DENUDED AND
HARDENED LAND FOR CROP GROWING, GRAZING OR FORESTRY. THE TECHNOLOGY
INVOLVES BUILDING LOW EMBANKMENTS WITH COMPACTED EARTH OR STONES IN THE
FORM OF A SEMI-CIRCLE WITH THE OPENING PERPENDICULAR TO THE FLOW OF WATER AND
ARRANGED IN STAGGERED ROWS.
• THEY ARE CONSTRUCTED ON GENTLY TO MODERATELY SLOPING PEDIMENTS AND PLATEAU
AREAS IN ORDER TO REHABILITATE AREAS THAT ARE DEGRADED, DENUDED AND/OR
AFFECTED BY SOIL CRUSTING. THE BUNDS REDUCE THE LOSS OF WATER AND THE FERTILE
LAYERS OF THE SOIL.

12.  COVER CROPS : ARE PLANTS THAT ARE PLANTED TO COVER THE SOIL RATHER THAN FOR
THE PURPOSE OF BEING HARVESTED. COVER CROPS MANAGE SOIL EROSION, SOIL
FERTILITY, SOIL QUALITY, WATER, WEEDS, PESTS, DISEASES, BIODIVERSITY AND WILDLIFE IN
AN AGROECOSYSTEM—AN ECOLOGICAL SYSTEM MANAGED AND SHAPED BY HUMANS.
COVER CROPS MAY BE AN OFF-SEASON CROP PLANTED AFTER HARVESTING THE CASH CROP.
THEY MAY GROW OVER WINTER
 DRIP IRRIGATION : DRIP IRRIGATION IS A TYPE OF MICRO-IRRIGATION SYSTEM THAT HAS
THE POTENTIAL TO SAVE WATER AND NUTRIENTS BY ALLOWING WATER TO DRIP SLOWLY TO
THE ROOTS OF PLANTS, EITHER FROM ABOVE THE SOIL SURFACE OR BURIED BELOW THE
SURFACE. THE GOAL IS TO PLACE WATER DIRECTLY INTO THE ROOT ZONE AND MINIMIZE
EVAPORATION.

13. CONSERVATION TILLAGE : TILLAGE SYSTEM THAT CREATES A SUITABLE SOIL
ENVIRONMENT FOR GROWING A CROP AND THAT CONSERVES SOIL, WATER AND ENERGY
RESOURCES MAINLY THROUGH THE REDUCTION IN THE INTENSITY OF TILLAGE (THE
PREPARATION OF LAND FOR GROWING CROPS.), AND RETENTION OF PLANT RESIDUES.
EXTERNAL CATCHMENT : INVOLVES DIRECTING RUNOFF WATER FROM THE SURROUNDING
AREA INTO A CATCHMENT WHICH CAN BE BENEFITTING PURPOSE OF DOMESTIC LIVESTOCK.
IT REQUIRES LARGE UNCULTIVATED LAND WHICH IS DIFFICULT IN LARGE POPULATED
AREAS

14.  EARTH BASINS: THESE ARE DESIGNED TO COLLECT AND HOLD RAINFALL THAT CAN BE
EASILY CONSTRUCTED BY HANDS THEY ARE SQUARE OR RECTANGLE IN SHAPE WITH EARTH
RIDGES ON ALL SIDES. RUNOFF WATER IS CHANNELLED TO LOWEST POINT IN AN
INFILTRATION PIT OR IN A SLOPING CORNER OR IN MIDDLE OF THE FLAT LAND.
 ROOF TOP HARVESTING : IT CAN STORE LARGE AMOUNT OF WATER IN RAINY SEASON.
RUNOFF FROM ROOFTOP IS COLLECTED IN PLASTIC GUTTERS AND DIVERTED INTO STORAGE
TANK AND ARE COVERED WITH OPAQUE COVERS.

15. Contour
farming
Stone
lines
Terrace
farming
Retention
Ditches

16. Semi circular bunds
Drip
irrigation
Conservation
tillage

17. DESIGNING OF SMALL STRUCTURES
1.MICRO CATCHMENT : IT IS A SPECIALLY CONTOURED AREA WITH SLOPE AND BERMS
DESIGNED TO INCREASE THE RUNOFF AND CONCENTRATE IT IN A PLANTING BASIN WHERE
INFILTRATION IS EFFECTIVELY STORED IN SOIL PROFILE.
 ADVANTAGES : THEY ARE SIMPLER AND ECONOMICAL TO CONSTRUCT AND CAN BE BUILT
RAPIDLY USING LOCAL MATERIAL. RUNOFF WATER HAS LOW SALT CONTENT,
TRANSPORTATION AND PUMPING CHARGES ARE NIL.
 SIZE : THEY ARE TYPICALLY SMALL SCULPTED BASIN WHICH HARVEST RUNOFF IN
LAMINAR FLOW WITH WATER DEPTH LESS THAN 1/8 INCHES AND FLOW VELOCITY LESS
THAN 2.75 INCHES.

18. SITE CONDITIONS : VARIOUS HYDROGRAPHIC FACTORS ARE TAKEN INTO ACCOUNT. A
DETAILED STUDY OF HYDROLOGICAL CYCLE FOR THAT PARTICULAR AREA WHICH HAS
INFORMATION SUCH AS :
1. RUNOFF PRODUCTION POTENTIAL
2. SOIL SURFACE CONDITIONS
3. WATER RETENTION CAPACITY
4. GRADIENT AND EVENNESS OF SLOPE
 CONSTRUCTION : CLEANING THE
CATCHMENT AREA FROM WEEDS.
 SHAPING THEM WITH HAND TOOLS AND GRADER
SMOOTHENING THE SURFACE
COMPACTION OF SOIL BY TOOLS

19. DESIGNING OF SMALL STRUCTURES
2. FORM POND : A LARGE HOLE DUG OUT IN THE EARTH USUALLY SQUARE OR RECTANGLE IN
SHAPE WHICH HARVEST RAINWATER AND STORE IT FOR FUTURE USE. THE SPECIFICATIONS
DEPEND ON FARMER’S REQUIREMENTS. THEY ARE USED FOR FISHING, IRRIGATION, WATER
SUPPLY CATTLE REARING ETC.
 TYPES : BASED ON LOCATION AND REQUIREMENT THEY ARE CLASSIFIED AS :
 DUGOUT PONDS
 SURFACE WATER PONDS
 SPRING OR CREEK
 OFF STREAM STORAGE

20.  SITE SELECTION : THE POND MUST BE LOCATED IN CORNER OF THE PLOT SO THAT ITS
OPERATION WILL NOT DISTURB FARMING PRACTICES.
MUST BE LOCATED AT LEAST 3M AWAY FROM FARMER’S FIELD
A SLOPE AND A SLOPE DIRECTION MUST BE CAREFULLY EVACUATED
 USE MACHINE FOR EXCAVATION AND TRANSPORTATIONS BEST FOR A FORM POND WITH
HUMANS FOR LEVELLING BUND FORMATION AND BUND CONSTRUCTION.
 ADVANTAGES : PROVIDE WATER FOR GROWING CROPS WITHOUT WAITING FOR RAINFALL
BUND CAN BE RAISED WITH VEGETABLES AND FRUIT TRESS WHICH CAN GET MORE INCOME
 CHECKS SOIL EROSION AND MINIMISES SILTATION OF WATER WAYS
PROVIDE WATER FOR LIVESTOCK AND DOMESTIC PURPOSE
RECHARGE GROUND WATER
PROMOTE FISH FARMING AND IMPROVE QUALITY OF DRAINAGE FLOW

21.  LIMITATIONS : IT REDUCES WATER FLOW TO OTHER LAKES AND PONDS SITUATED IN LOW
LYING AREAS
 THEY OCCUPY A LARGE SPACE
SALINE/SALT CONTENT ON THAT PARTICULAR AREA INCREASES
3. PERCOLATION TANKS : THESE ARE MOSTLY EARTHEN DAMS WITH MANY MASONARY
STRUCTURES ONLY FOR SPILLWAY. THESE ARE MORE PREVALENT STRUCTURES IN INDIA.
 THESE ARE ARTIFICIALLY CREATED SURFACE WATER BODIES MERGING IN ITS RESERVIOUR
A HIGHLY PERMEABLE LAND TO THAT THE SURFACE RUNOFF IS MADE TO PERCOLATE AND
RECHARGE THE GROUND WATER.
CONSTRUCTION : THEY SHOULD BE CONSTRUCTED PREFERABLY FROM 2ND TO 4TH ORDER
STREAMS WHICH ARE LOCATED ON A HIGHLY FRACTURED AND WEATHERED ROCKS WHICH
HAVE LATERAL CONTINUITY.

22.  THE AQUIFER WHICH IS TO BE RECHARGED SHOULD HAVE SUFFICIENT THICKNESS AND
PERMEABLE VOIDS TO RECHARGE .
THE DOWNSTREAM OF RECHARGE AREA SHOULD HAVE SUFFICIENT NUMBER OF WELLS AND
CULTIVATED AREA TO GET BENEFIT FROM THE AUGMENTATION OF GROUND WATER.
THE PERCOLATION TANK IS SIMILAR TO CHECK DAMS OR NALAAS WITH LARGE STORAGE
RESERVOIR.
THE CONSTRUCTION MATERIAL IS MIXTURE OF SOIL SILT CLAY SAND GRAVEL WHICH ARE
SUITABLY MIXED AND ARE MADE LAYERS TO GET PERFECT STABILITY AND WATER
TIGHTNESS.
THESE ARE POPULAR IN MAHARASHTRA, AP, KARNATAKA, MADHYA PRADESH, TAMILNADU,
AND GUJRAT.

24. RAIN WATER HARVESTING
• RAINWATER HARVESTING IS A TYPE OF HARVEST IN WHICH THE RAIN DROPS ARE
COLLECTED AND STORED FOR THE FUTURE USE, RATHER THAN ALLOWING THEM TO RUN
OFF.
• RAINWATER CAN BE COLLECTED FROM RIVERS OR ROOFS AND REDIRECTED TO A DEEP PIT
(WELL, SHAFT, OR BOREHOLE), AQUIFER, A RESERVOIR WITH PERCOLATION, OR COLLECTED
FROM DEW OR FOG WITH NETS OR OTHER TOOLS.
• ITS USES INCLUDE WATER FOR GARDENS, LIVESTOCK, IRRIGATION, DOMESTIC USE WITH
PROPER TREATMENT, INDOOR HEATING FOR HOUSES, ETC.
• THE HARVESTED WATER CAN ALSO BE USED AS DRINKING WATER, LONGER-TERM STORAGE,
AND FOR OTHER PURPOSES SUCH AS GROUNDWATER RECHARGE.
• RAINWATER HARVESTING IS ONE OF THE SIMPLEST AND OLDEST METHODS OF SELF-SUPPLY
OF WATER FOR HOUSEHOLDS USUALLY FINANCED BY THE USER.
• IT’S A GOOD OPTION WHERE QUALITY OF SURFACE WATER IS GOOD AND HAS LESS
GROUNDWATER

25. RAIN WATER HARVESTING
 METHODS OF RWH : THEY ARE CLASSIFIED AS
1. SURFACE RUNOFF HARVESTING : IN URBAN AREAS, RAINWATER FLOWS AS SURFACE
RUNOFF, THIS RUNOFF CAN BE COLLECTED AND USED FOR RECHARGING AQUIFERS BY
ADOPTING APPROPRIATE METHODS
2. ROOFTOP HARVESTING : HERE, THE ROOF BECOMES THE CATCHMENT AREAAND
RAINWATER IS COLLECTED FROM THE ROOFTOPS OF BUILDING.
 IT CAN EITHER BE STORED IN A TANK OR DIVERTED TO ARTIFICIAL RECHARGE SYSTEM.
 THIS METHOD IS LESS EXPENSIVE AND ARE VERY EFFECTIVE IF IMPLEMENTED PROPERLY
WHICH WILL IN TURN HELP THE GROUNDWATER LEVEL OF AREA.

26. RAIN WATER HARVESTING
 COMPONENTS OF MODERN RWH :
 ROOFTOP CATCHMENT
GUTTERS
DOWNPIPE
FIRST FLUSH PIPE
FILLER UNIT
STORAGE TANK
COLLECTION PIT

27. RAIN WATER HARVESTING
 ADVANTAGES OF RWH :
 SUITABLE FOR IRRIGATION
 REDUCES DEMAND FOR GROUND WATER
 REDUCE FLOODS AND SOIL EROSION
 REDUCE WATER BILLS
 USED FOR NON DRINKING PURPOSE
 DISADVANTAGES :
 UNPRIDICTABLE RAINFALL
 INITIAL HIGH COST
 STORAGE LIMIT
ROOFTOPS MAY HAVE CHEMICALS
 REGULAR MAINTAINAVCE