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

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

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)

Water user group [Cambodia]

A water user group, led by a committee staff, decides about the distribution of the water during the dry season to plant dry season rice.

• Compiler: Stefan Graf
• 10/27/2014 midnight

2.1 Short description of the Technology

Definition of the Technology:

Norias are water-pumping wheels made of bamboo which are used to irrigate paddy fields in order to increase the yield.

2.2 Detailed description of the Technology

Description:

Norias are undershot waterwheels used to pump up water. They are a traditional technology in south-east Asia, where the technology is passed on from father to son. Norias are traditionally made of bamboo and wood. The stream powers the wheel; the bamboo tubes closed at one end fill with water, carry it up and release it in a trough which flows to the fields. To avoid damages from floating debris and water plants, a diverting bamboo fence is built upstream.
When the water level in the river is lower, an underwater bound is built to direct it toward the wheel and ensure a continuous pumping. This is done around three times a year. In case of a flood, the waterwheel can be damaged or destroyed, which occurs around once a year. The noria described in this case study is in use from June to November, as the river dries out. With its 3 m diameter it allows the production of two rice harvests a year on 2.5 ha. During the dry season, it is removed and repaired.

The purpose of this irrigation device is to ensure a permanent water access in the rice field, and to produce 2 harvests instead of one per year. The norias are low cost devices which are built by the farmer themselves, but can only be used to irrigate fields which are located close to a river.

To build a noria, an experienced farmer only needs around one day, and wood and bamboo worth around 25 US$. It is installed at the beginning of the rainy season, and removed at the end to be fixed. In case of floods (which happens around once a year) it also needs to be fixed. The maintenance costs are around a quarter of the establishment costs. When the water level drops, a berm is built in the water to redirect the water toward the wheel, which is needed around three times a year. With this berm, the speed and thus pumping of water can be regulated.

The analysed area is flat (slope < 2%), with a tropical climate (dry and wet season), and the soils are mostly sandy or loamy. The soils contain little organic matter (low soil fertility, acidification, small amount of cattle, area has been deforested a long time ago) and the groundwater table is rather high (2 m below soil level during the dry season, on the surface during the wet season). There are many temporary and a few permanent streams in the area.
Due to climate change, the rainfalls are more erratic, temperatures rise and droughts are more recurrent. Rice is the predominant crop grown in the area, since it serves as staple food (mix subsistence and commercial activities). Rice is often grown in monocultures and harvested once a year. Once the rice is harvested (dry season), some farmers release cattle to the paddy fields to eat the straw and weeds.

As an addition to rice, most land users grow vegetables and fruits in small home gardens (subsistence) and complement their income by producing handicrafts or through off-farm income / remittances from family members working in other places. The increasing migration rate (the young generation leaves the villages to work in the cities, garment industry or abroad) results in a decrease of available labour force in the area which has detrimental effects on the agricultural activities. Furthermore, the civil war in the 1970s (Khmer Rouge) led to the loss of agricultural knowledge which different NGOs try to re-establish.

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:

Cambodia

Region/ State/ Province:

Kampong Chhnang

Further specification of location:

Toeuk Phos

Specify the spread of the Technology:

• evenly spread over an area

If precise area is not known, indicate approximate area covered:

• 0.1-1 km2

Map

×

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:

• as part of a traditional system (> 50 years)

Comments (type of project, etc.):

Norias are a traditional setting in south-east Asia. The farmer from this case study learned it from his father, and the family continuously used them for generations (except during the Pol Pot regime).

3.1 Main purpose(s) of the Technology

• improve production
• create beneficial economic impact

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

Cropland

• Annual cropping

Annual cropping - Specify crops:

• cereals - rice (wetland)

Number of growing seasons per year:

• 1

Specify:

Longest growing period in days: 210, Longest growing period from month to month: June-December

Waterways, waterbodies, wetlands

Comments:

Major land use problems (compiler’s opinion): Low soil fertility, lack of irrigation, monocultures, overgrazing, soil left bare after ploughing.
Major land use problems (land users’ perception): Lack of irrigation.
Livestock is grazing on crop residues

3.4 Water supply

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

• mixed rainfed-irrigated

3.5 SLM group to which the Technology belongs

• irrigation management (incl. water supply, drainage)
• water diversion and drainage

3.6 SLM measures comprising the Technology

structural measures

• S11: Others

3.7 Main types of land degradation addressed by the Technology

water degradation

• Ha: aridification

Comments:

Main causes of degradation: soil management, crop management (annual, perennial, tree/shrub) (Rice monocultures, with soil left bare after ploughing.), droughts (More erratic rainfall.)
Secondary causes of degradation: overgrazing (Uncontrolled grazing of cattle.), change in temperature (More hot days.)

3.8 Prevention, reduction, or restoration of land degradation

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

• reduce land degradation
• restore/ rehabilitate severely degraded land

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

4.3 Establishment activities

4.4 Costs and inputs needed for establishment

4.5 Maintenance/ recurrent activities

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

Comments:

Machinery/ tools: hatchet, saw, drill
The costs were calculated in 2014 for a noria of around 3 m diameter, irrigating 2.5 ha of rice fields.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The availability of wood and bamboo determines the costs.

5.1 Climate

5.2 Topography

5.3 Soils

5.4 Water availability and quality

Comments and further specifications on water quality and quantity:

during dry seasons

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users
Difference in the involvement of women and men: Heavy labour, and skills are passed on from father to son.
Population density: 10-50 persons/km2
Annual population growth: 0.5% - 1% (Rich farmers use pumps, poor farmers do not have land near the river.).
Off-farm income specification: Handicraft, remittances, and factory work.

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

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

Land ownership:

• communal/ village
• individual, not titled

Land use rights:

• communal (organized)
• individual

Water use rights:

• open access (unorganized)

Comments:

Land users have a title that is not recognized by the state.

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Water availability and quality

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

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

Climate-related extremes (disasters)

Meteorological disasters

Climatological disasters

Hydrological disasters

Other climate-related consequences

Other climate-related consequences

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

• 91-100%

Comments:

100% of land user families have adopted the Technology without any external material support
5 land user families have adopted the Technology without any external material support
There is no trend towards spontaneous adoption of the Technology
The suitable water streams are given, norias can only irrigate areas close to streams.

6.7 Strengths/ advantages/ opportunities of the Technology

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

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

FAO report on water pumping devices.

Available from where? Costs?

http://www.fao.org/docrep/010/ah810e/ah810e12.htm