Technologies

Plastic-lined conservation pond to store irrigation water [Nepal]

Plastic bichchhayeko Samrakshan pokhari - Nepali

technologies_1462 - Nepal

Completeness: 76%

1. General information

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:
SLM specialist:
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
International Centre for Integrated Mountain Development (ICIMOD) - Nepal

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

A plastic-lined dugout pond to store runoff and household wastewater for irrigation purposes during dry periods

2.2 Detailed description of the Technology

Description:

Water harvesting technology is very useful in areas where there is limited rainfall for long periods of the year. These dry periods severely limit the growing of crops across Nepal’s middle mountains especially on steep slopes where conventional irrigation can be difficult to arrange. Plastic-lined conservation ponds store water for irrigation more efficiently than the traditional earthen ponds which lose much water to seepage.
The ponds are dug out and the earthen walls lined with high density polyethylene (HDPE) sheet or SILPAULIN (multi-layered, cross laminated, UV stabilised) heavy duty plastic sheeting. The size of the pond will vary depending on the area available and the soil characteristics. The PARDYP project tested and demonstrated plastic-lined ponds with a capacity of 8,000-10,000 litres. These ponds were about 3m long, 2m wide and 1.5m deep and were located at shady sites to minimise evaporation losses. The conservation ponds tested and demonstrated by the PARDYP project were used for irrigating high value off-season horticultural crops (vegetables, fruit, and spices). These crops were irrigated with drip irrigation and micro sprinklers (see sheets QT NEP6 and QT NEP21). The ponds were fed from rainwater, upland springs and taps, and household wastewater. The ponds were established during the dry season in three days. They were prepared by selecting a suitable site with a sufficient catchment; mapping out the area and depth of the pond; digging out the soil; removing protruding stones and roots; and compacting and smoothing the sides and bottom of the pond. Then the sides and bottom of the pond were lined with sieved soil followed by plastic sheet, which was anchored by stones and soil.
The main maintenance activity is to prevent livestock and people from entering the pond to avoid damaging the sheet. The pond should not be allowed to dry up as this would let rats damage the sheet. The sediment that accumulates in the pond should be removed once a year carefully by hand only as the use of agricultural tools could puncture the sheet.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Nepal

Further specification of location:

Kavrepalanchowk district/ Lamdihi, Patalekhet, Chiuribot, villages of Jhikhu Khola watershed

Specify the spread of the Technology:
  • applied at specific points/ concentrated on a small area

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • more than 50 years ago (traditional)

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through projects/ external interventions
Comments (type of project, etc.):

It is an ancient water management technique, later adapted according to the local condition.

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • Improve water availability

3.2 Current land use type(s) where the Technology is applied

Cropland

Cropland

  • Annual cropping
Annual cropping - Specify crops:
  • cereals - maize
  • legumes and pulses - other
  • root/tuber crops - potatoes
  • seed crops - sesame, poppy, mustard, other
  • rice, wheat, tomato
Number of growing seasons per year:
  • 3
Specify:

Longest growing period in days: 150; Longest growing period from month to month: Jun - Oct; Second longest growing period in days: 120; Second longest growing period from month to month: Nov - Feb

Comments:

major cash crop: Tomato and potato
major food crop: Rice and wheat
other: Mustard and legumes

Major land use problems (compiler’s opinion): 1. Small landholdings which are mostly rainfed for cropping.
2. Low soil fertility status and high susceptibility to erosion.
3. Limited supplies of irrigation water and poor irrigation infrastructure.

Major land use problems (land users’ perception): The farmers experience serious constraints in terms of adopting better farming options, e.g., cash crops due to soil fertility and soil moisture problems.

Type of cropping system and major crops comments: Maize- wheat/ vegetables

3.4 Water supply

Water supply for the land on which the Technology is applied:
  • rainfed

3.5 SLM group to which the Technology belongs

  • water harvesting

3.6 SLM measures comprising the Technology

structural measures

structural measures

  • S4: Level ditches, pits

3.7 Main types of land degradation addressed by the Technology

water degradation

water degradation

  • Hs: change in quantity of surface water

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • reduce land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Plastic- linined conservation pond

Location: Patalekhet, Lamdihi and Chiurobot.. Kavrepalanchowk

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: moderate

Main technical functions: water harvesting / increase water supply

Secondary technical functions: control of dispersed runoff: retain / trap

Structural measure: pond
Depth of ditches/pits/dams (m): 1.5
Width of ditches/pits/dams (m): 2
Length of ditches/pits/dams (m): 3

Construction material (earth): It is a earth excavated pit with earthen side walls

Construction material (other): plasitc sheet - Lining of a HDPE sheet or SILPAULIN (Multi-layered, cross laminated, UV stabilized p

Author:

A.K. Thaku, Madhav Dhakal

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:
  • per Technology unit
Specify unit:

Pond

Specify dimensions of unit (if relevant):

3m long, 2m wide and 1.5m deep

Specify currency used for cost calculations:
  • USD
Indicate average wage cost of hired labour per day:

2.10

4.3 Establishment activities

Activity Timing (season)
1. Select a preferably fl at site with a suffi cient catchment area dry months
2. Measure the area to be irrigated and estimate the size of the pond dry months
3. Measure and mark out the pond 1st day
4. Dig out the soil to the pre-determined depth 1st day
5. Remove protruding stones and roots 2nd day
6. Compacting and smooting the sides and bottom of the pond. 2nd day
7. Line the sides and bottom of the pond with sieved soil (preferably a clay 2nd day
8. Lay out the plastic sheets without any folds over the pond with 3rd day
9. Overlay thick fine soil on the plastic sheet 3rd day
10. Anchor the edges of the sheet at the rim of the pond with stones and soil. 3rd day

4.4 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Dig out pond persons/unit 3.0 2.1 6.3 100.0
Equipment Plastic unit 1.0 29.2 29.2
Total costs for establishment of the Technology 35.5
Total costs for establishment of the Technology in USD 35.5
Comments:

Duration of establishment phase: 3 month(s)

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Prevent livestock and humans from entering the pond daily/regularly
2. Ensure that the pond is not allowed to dry out completely as this could dry months./regularly,
3. Removing accumulated sediment once a year carefully by hand (using dry months./once in a year.

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Clean and maitaining the pond persons/unit 3.0 2.1 6.3 100.0
Total costs for maintenance of the Technology 6.3
Total costs for maintenance of the Technology in USD 6.3
Comments:

Machinery/ tools: measuring tape, spade, shovel, knife, hoe, hammer, trowel, and pan

The cost given above is for unit technology having 9000 litre capacity as in 2006.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Cost of plastic, members of a household contributed as labour in all sites.

5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specify average annual rainfall (if known), in mm:

1070.00

Agro-climatic zone
  • humid

Thermal climate class: subtropics

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms:
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • medium (loamy, silty)
  • fine/ heavy (clay)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil fertility is medium

Soil drainage / infiltration is good

Soil water storage capacity is medium

5.4 Water availability and quality

Water quality (untreated):

poor drinking water (treatment required)

Comments and further specifications on water quality and quantity:

Water quality (untreated): Also good. More in rainy season (June- September), less in April/May; source: spring

5.6 Characteristics of land users applying the Technology

Market orientation of production system:
  • mixed (subsistence/ commercial)
Off-farm income:
  • 10-50% of all income
Relative level of wealth:
  • poor
  • average
Individuals or groups:
  • individual/ household
Level of mechanization:
  • manual work
  • animal traction
Gender:
  • women
  • men
Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users

Population density: 200-500 persons/km2

Annual population growth: 2% - 3%

80% of the land users are average wealthy and own 90% of the land (ranked by land users).
20% of the land users are poor and own 10% of the land.

Off-farm income specification: In most farm households, off-farm income plays at least a minor and
increasingly a major role. Occasional opportunities for off-farm income present themselves in the form of daily
labour wages. Some households’ members receive regular salaries, whilst an increasing number of Nepalis are
working in India, the Middle East, Malaysia, and elsewhere and sending remittance incomes home.

Market orientation of production system: Vegetables- commercial

Level of mechanization: Manual labour consists of planting, irrigation , harvesting, while field field preparation is carried out by animals, also machines but just in valley bottom.

5.7 Average area of land used by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
  • medium-scale

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • individual, titled
Land use rights:
  • individual
Water use rights:
  • open access (unorganized)
  • communal (organized)

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

production area

decreased
increased

land management

hindered
simplified
Income and costs

farm income

decreased
increased
Comments/ specify:

due to availability of more water for irrigation

Socio-cultural impacts

community institutions

weakened
strengthened
Comments/ specify:

due to informal network of farmers with ponds

SLM/ land degradation knowledge

reduced
improved
Comments/ specify:

farmers discuss and share experiences

livelihood and human well-being

reduced
improved
Comments/ specify:

increased vegetable production, more income from vegetables.

Ecological impacts

Soil

soil moisture

decreased
increased

soil cover

reduced
improved
Comments/ specify:

fallow land is turned into cropped land

6.2 Off-site impacts the Technology has shown

downstream flooding

increased
reduced
Comments/ specify:

due to trapped runoff

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change
Season increase or decrease How does the Technology cope with it?
annual temperature increase not known

Climate-related extremes (disasters)

Meteorological disasters
How does the Technology cope with it?
local rainstorm well
local windstorm well
Climatological disasters
How does the Technology cope with it?
drought not well
Hydrological disasters
How does the Technology cope with it?
general (river) flood not well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
reduced growing period well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

positive

Long-term returns:

very positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

very positive

Long-term returns:

very positive

Comments:

Perception of land users who accepted the technology by getting
incentives from the PARDYP project. If incentives are not available the short-term costs and benefits would be equal.

6.5 Adoption of the Technology

  • > 50%
If available, quantify (no. of households and/ or area covered):

5 households in an area of 10 ha

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 0-10%
Comments:

100% of land user families have adopted the Technology with external material support

5 land user families have adopted the Technology with external material support

Comments on acceptance with external material support: survey results

Comments on spontaneous adoption: survey results

There is no trend towards spontaneous adoption of the Technology

Comments on adoption trend: because of the expense of the plastic sheet and it not being locally available

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Water is sufficient to irrigate 2-3 ropani( 1 ropani = 508 sq.m.)land in one season.

How can they be sustained / enhanced? Advantages of the technology should be shared with large number of people.
Plastic pond lasted more than 5 years and it is leak proof.
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Good income from sales of vegetables in the dry season can be achieved even from a small piece of land

How can they be sustained / enhanced? Advantages of the technology should be more widely shared
The source of water for these ponds was not only rainwater but also other sources like springs and taps, These ponds are fed with rainwater and household wastewater and from springs and taps. The ponded water was mainly used for micro irrigation including drip irrigation and micro-sprinklers

How can they be sustained / enhanced? Promote the use of other water conserving techniques like mulching when using the harvested water
Reduced the dependence on large scale water supply schemes

How can they be sustained / enhanced? Harvest all possible sources of water
No seepage loss observed fi ve years after building the ponds meaning that the plastic lasts at least five years

How can they be sustained / enhanced? Continue trials

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view How can they be overcome?
Plastic pond is expensive for poor farmers. subsidised cost for poors
unsafe for small childrens Protection structures should be constructed.
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
SILPAULIN (multi-layered, cross laminated, UV stabilized) heavy duty plastic is not available in local markets and is expensive for poor farmers Make it available in the local market at a subsidised cost for poor farmers.
The ponds attract insects, mainly mosquitoes, that cause disease; and the ponds are unsafe for small children Regularly clean the pond and fence them in

7. References and links

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

ICIMOD (2007) Good Practices in Watershed Management, Lessons Learned in the Mid Hills of Nepal. Kathmandu: ICIMOD

Available from where? Costs?

ICIMOD

Title, author, year, ISBN:

SCWMC (2004) Soil Conservation and Watershed Management Measures and Low Cost Techniques. Kathmandu: Government of Nepal, Soil Conservation and Watershed Management Component - Department of Soil Conservation and Watershed Management

Available from where? Costs?

DSCWM, Kathmandu

Title, author, year, ISBN:

Shafi q, M.; Ikram, M.Z.; Nasir, A. (1995) Water Harvesting Techniques for Sustainable Agriculture in Dry and Cold Mountain Areas. Paperpresented at the Workshop on Sustainable Agriculture in Dry and Cold Mountain Areas, Pakistan Agricultural Research Council, 25-27 September1995, Queta, Pakistan

Available from where? Costs?

ICIMOD

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