1.2 Контактные данные специалистов и организаций, участвующих в описании и оценке Технологии

Название проекта, содействовавшего документированию/оценке Технологии (если применимо)

Book project: Water Harvesting – Guidelines to Good Practice (Water Harvesting)

Название организации (-ий), содействовавших документированию/оценке Технологии (если применимо)

Africa Sand Dam Foundation (ASDF) - Кения

Название организации (-ий), содействовавших документированию/оценке Технологии (если применимо)

Excellent Development Ltd. (Excellent Development Ltd.) - Великобритания

1.3 Условия, регламентирующие использование данных, собранных ВОКАТ

Составитель и ответственный(-ые) специалист(-ы) согласны с условиями, регламентирующими использование собранных ВОКАТ данных:

Да

2.1 Краткое описание Технологии

Определение Технологии:

A sand dam is a stone masonry barrier across a seasonal sandy riverbed that traps rainwater and sand flowing down the catchment.

2.2 Подробное описание Технологии

Описание:

A sand dam is typically 1 - 5 metres high and 10-50 metres across. When it rains the dam captures soil laden water behind it – the sand in the water sinks to the bottom, whilst the silt remains suspended in the water. Eventually the dams fill with sand - sometimes after only one rainfall or over 1 – 3 seasons. 25 to 40% of the volume of the sand held is actually water. A mature sand dam can store millions of litres of water – refilling after each rainfall providing a year round supply to over 1,000 people.

Purpose of the Technology: Sand dams are a simple, low cost and low maintenance, replicable rainwater harvesting technology. They provide a clean, local water supply for domestic and farming use and are suited to arid and semi-arid areas of the world. It is a solution that is scaleable and has a broader application for use as a rural and game park road crossing to replace less effective culvert bridges.

Establishment / maintenance activities and inputs: Sand dams are the lowest cost form of rainwater harvesting and its robust nature and very low operational and maintenance costs make it particularly suited to remote and poorly served regions. A typical dam using 500 bags of cement would approx be 40 metres in length with a spillway 2 metres above the bedrock. The dam is constructed using stone masonry placed in timber formwork. Such a dam costs approximately USD 11,800 (in 2012 prices). This consists of materials (cement, steel reinforcement, timber, transport) and dam permit USD 8,800 (75%), project management including technical support from skilled local artisans and dam designers USD 2150 (18%) and finance and administration costs of implementing organisation USD 850 (7%). Local people freely contribute their labour to collect rock, sand and water, terrace and protect the immediate catchment and construct the dam. If this contribution was costed and included the cost of the dam would almost double. The maintenance and repair costs of the dam provided it has been well designed and constructed is negligible. Local users are responsible for the management and repair of the dam and its abstraction system. Where a hand pump is fitted, local users fund the repair and replacement of the pump as required. The purchase and repair of petrol powered water pumps which some groups use to irrigate adjacent land is the responsibility of the members of the local group.

Natural / human environment: Because the water is stored within the sand, evaporation losses are very low, the sand filters the water and water-vector diseases such as malaria are controlled. Sand dams provide significant environmental benefits such as aquifer recharge, increased downstream flows in the dry-season, rejuvenation of river ecologies and moderation of floods. As such, it contributes to ecosystem services and climate change adaption.

2.3 Фотографии, иллюстрирующие Технологию

2.5 Страна/ регион/ места, где применяется Технология, информация о которых собрана в данной Анкете

2.6 Сколько лет применяется данная Технология

Если год начала применения Технологии достоверно неизвестен, дайте примерную оценку:

• 10-50 лет назад

2.7 Внедрение Технологии

Укажите, как именно Технология УЗП была внедрена:

• через проекты/ внешнее вмешательство

Пояснения (тип проекта и т.д.):

Sand dams are an ancient technology. Examples are found across the world's drylands although the greatest concentration is found in Kenya. They were introduced to Kenya in the 1950s from India. Dams were pioneered in Machakos and Makueni counties of Kenya by Joshua Mukusya, a visionary farmer and development worker, in 1978. He worked with a range of agencies to develop and implement the technology. In 1990, staff trained by Joshua set up SASOL to pioneer sand dams in the neighbouring county of Kitui. In 2002, Joshua teamed up with Simon Maddrell, Excellent Development's director, to establish Excellent Development Kenya, now Utooni Development Organisation (UDO) to scale up the work. Sadly, in 2011, Joshua passed away. In 2010, Excellent Development formed a strategic partnership with the Kenyan NGO, Africa Sand Dam Foundation (ASDF), to support the wider uptake beyond Kenya. Today, ASDF, SASOL and UDO are the three NGOs with the most experience of building successful sand dams, approx. 130 dams / year, although many other NGOs have adopted the technology.

3.1 Основные цели и задачи реализации Технологии

• access to water

3.2 Текущий(-ие) тип(-ы) землепользования на территории, где применяется Технология

Пояснения:

Major land use problems (compiler’s opinion): Drylands are characterised by intense and variable rainfall and a lack of vegetative cover. As a result, drylands are prone to droughts, flooding and soil erosion which result in endemic water and food scarcity.

Major land use problems (land users’ perception): “We used to fetch water from Londokwe; we could spend a night to collect water. One way was 3 to 10 km and up to 12 hours or more to go and come back [because of the time taken to queue]. If we could not make it to the river, we would send our children to fetch water. When they went fetching water that would mean they did not go to school. At times people would fight over fetching water from other people’s scoop holes. Scoop holes would be guarded in turns. The gourds [water containers] would be damaged and the water poured down. Children would not go to school [as they needed to] take care of the young ones as the parents went to fetch water. Children would fail to go to school because they were hungry – just because there was no water to cook."
Yikiuuku SHG

3.5 Категория УЗП, к которой относится Технология

• сбор атмосферных осадков

3.6 Мероприятия УЗП, выполняемые в рамках Технологии

Пояснения:

Main measures: structural measures

3.7 Основные проблемы деградации земель, на решение которых направлена Технология

Пояснения:

Main type of degradation addressed: Hs: change in quantity of surface water

Secondary types of degradation addressed: Bq: quantity / biomass decline, Bs: quality and species composition /diversity decline, Ha: aridification, Hg: change in groundwater / aquifer level

Main causes of degradation: Heavy / extreme rainfall (intensity/amounts), droughts

3.8 Предотвращение и снижение деградации земель, или восстановление нарушенных земель

Укажите цель Технологии по отношению к деградации земель :

• предотвращение деградации земель
• снижение деградации земель

4.1 Технический рисунок, иллюстрирующий Технологию

4.2 Общая информация по необходимым вложениям и стоимости

другая/ национальная валюта (название):

Kenyan Shilling

Если это необходимо, укажите обменный курс от доллара США к местной валюте (например, 1 доллар США = 79,9 бразильского реала): 1 доллар США =:

83,0

4.3 Мероприятия, необходимые для начала реализации

	Деятельность	Время (сессия)
1.	Collection of rock, sand and water	1-3 months before construction
2.	Construct dam	During dry season
3.	Cure dam	For 4 weeks after construction
4.	Terracing and protection of immediate catchment	1-3 months before construction

4.4 Вложения и затраты, необходимые для начала реализации

	Опишите затраты	Единица	Количество	Затраты на единицу	Общая стоимость на единицу	% затрат, оплаченных землепользователями
Оплата труда	Collection of rock, sand and water	Persons/day	220,0	2,5	550,0	100,0
Оплата труда	Terracing and protection of immediate catchment	Persons/day	100,0	2,5	250,0	100,0
Оплата труда	Construct dam	Persons/day	500,0	2,5	1250,0	90,0
Оплата труда	Cure dam	Persons/day	50,0	2,5	125,0	100,0
Оборудование	Tools	per dam	1,0	300,0	300,0
Строительные материалы	Cement (bag = 50kg)	bags	500,0	9,15	4575,0
Строительные материалы	Steel (12m x Y20 steel bar)	pieces	7,0	45,7	319,9
Строительные материалы	Steel	per dam	1,0	1000,0	1000,0
Другие	Skilled labour	per dam	1,0	3000,0	3000,0
Общая стоимость запуска Технологии					11369,9
Общие затраты на создание Технологии в долларах США					136,99

Пояснения:

Duration of establishment phase: 6 month(s)

4.5 Поддержание/ текущее обслуживание

	Деятельность	Сроки/ повторяемость проведения
1.	Inspect and if necessary extend spillway or repair erosion around dam	As required / annually
2.	Maintain hand pump if fitted	As required / annually

4.6 Стоимость поддержания/ текущего обслуживания ( в год)

Пояснения:

In 2012, in Machakos County, Kenya, the cost of materials and technical support for a dam using 250 bags of cement is USD 7,000 and USD 11,700 for a 500 bag dam. The costs in 2.6.1 are based on a 500 bag dam. The volume of a 500 bag dam is approx 140m3 of stone masonry of which 40% is mortar (sand and cement) and 60% is rock. Such a dam will typically be appropriate on rivers 30m wide and with a spillway 3 metres above the bedrock in the river bed level. Costs rise by up to 50% in more remote regions or countries. Sand dams require a lot of hard work. Community members collect the required stones, sand and water, support construction and terrace the land around the dam. If this in-kind contribution is included the costs would rise by 100%. In Kenya, with a long tradition of building sand dams, it takes from 6 to 12 weeks to plan and prepare for construction and 2 days to 2 weeks to build the dam. In other areas, with less experience and/or less community commitment, building a dam may take 6 months or more.

4.7 Наиболее значимые факторы, влияющие на стоимость затрат

Опишите наиболее значимые факторы, влияющие на стоимость затрат:

Each dam is individually designed. The size, design and cost of a dam varies considerably with the size of the river and to a lesser extent, location and transport costs. Sand dams are the world’s lowest cost method of capturing rainwater in dry rural areas by a factor of 3 to 30 times compared to rain water harvesting tanks, earth dams, haffirs and rock catchments.

5.1 Климат

5.2 Рельеф

Комментарии и дополнительные сведения по условиям рельефа/ топографии :

Land forms: Sand dams only suit seasonal rivers with sufficient sandy sediment and an accessible bedrock

Altitudinal zone: Also 1,001-1,500 m a.s.l.

Slopes on average: Also moderate

5.3 Почвы

Если возможно, приложите полное описание почв или укажите доступную информацию, например тип почв, рH/ кислотность почв, ёмкость катионного обмена, содержание азота, содержание солей и т.д.

Soil water storage capacity: The aquifer behind the dam must consist of sandy sediments with a high porosity and drainable porosity

5.4 Доступность и качество воды

Комментарии и дополнительная информация по качеству и количеству воды:

Availability of surface water: Sand dams only suit seasonal rivers

Water quality (untreated): Good drinking water because the sand filters the water. Water abstracted through an infiltration gallery has a high bacterialogical quality but water is often used for small scale irrigation and livestock watering.

5.5 Биоразнообразие

Комментарии и дополнительная информация по биоразнообразию:

Sand dams rejuvenate riverine ecologies and increase local biodiversity

5.6 Характеристика землепользователей, применяющих Технологию

Укажите другие важные характеристики землепользователей:

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

Difference in the involvement of women and men: The dams are built by members of registered self-help groups, typically 50 members / group and two-thirds women. The primary concerns of these groups tend to be food and water. Sand dams provide for people, livestock and crops. Water collection and farming are primarily undertaken by women in Kikamba culture and hence women have the greatest vested interest to imrpove food and water availability. Many men migrate away from the area in search of work.

Population density: 50-100 persons/km2

Annual population growth: 2% - 3%

Off-farm income specification: This varies considerably, but most self-help group members are subsistence farmers

5.7 Средняя площадь земель, используемых землепользователями с применением Технологии

5.8 Собственность на землю, права на земле- и водопользование

Землевладелец:

• государственная

Право землепользования:

• общинное (контролируемое)

Право водопользования:

• общинное (контролируемое)

Пояснения:

Legal agreements for construction and access between the self-help group and the owners of land adjacent to the dam and registering the dam and its associated water rights by the self-help group with the Kenyan Water Resources Management Authority (WRMA) is vital to safeguarding water rights, controlling water and sand abstraction, formalising the authority of the self-help group to levy water tarriffs if appropriate and ensuring there is open access to all to water from scoop holes.

5.9 Доступ к базовым услугам и инфраструктуре

6.1 Влияние Технологии УЗП в пределах территории ее применения

Социально-экономическое воздействие

Продуктивность

Доступность и качество воды

Доходы и затраты

Другое социально-экономическое воздействие

Социальное и культурное воздействие

Экологическое воздействие

Водный цикл/ поверхностный сток

Почвы

Биоразнообразие: растительность, животный мир

Климат и снижение риска стихийных бедствий

6.2 Влияние Технологии за пределами территории ее применения

6.3 Подверженность и чувствительность Технологии УЗП к постепенным изменениям климата и экстремальным погодным явлениям/ стихийным бедствиям, связанным с изменением климата (в понимании землепользователей)

Постепенное изменение климата

Постепенное изменение климата

	Сезон	увеличение или уменьшение	Насколько успешно Технология справляется с этим?
среднегодовые температуры		увеличилось	хорошо

Экстремальные явления, связанные с изменением климата (стихийные бедствия)

Погодные стихийные бедствия

	Насколько успешно Технология справляется с этим?
местные ливневые дожди	хорошо
местные ураганы	хорошо

Стихийные бедствия климатического характера

	Насколько успешно Технология справляется с этим?
засухи	хорошо

Гидрологические стихийные бедствия

	Насколько успешно Технология справляется с этим?
регулярные наводнения (выход рек из берегов)	хорошо

Другие воздействия, связанные с изменением климата

Другие воздействия, связанные с изменением климата

	Насколько успешно Технология справляется с этим?
сокращение вегетационного периода	хорошо

Пояснения:

The capacity of the spillway would be increased to control peak flood events

6.4 Анализ эффективности затрат

Насколько получаемый результат сопоставим с первоначальными вложениями (с точки зрения землепользователей)?

Насколько получаемый результат сопоставим с текущими расходами по поддержанию технологии (с точки зрения землепользователей)?

Пояснения:

The very low cost of operating and maintaining sand dams means they are well suited to remote, poorly served regions. Because it is a low cost technology that requires a major community contribution and the knowledge and skills of locally trained artisans, it’s a solution particularly suited to community ownership and self-supply. This contributes to effective implementation.

6.5 Внедрение Технологии

Среди применяющих Технологию землепользователей, какова доля лиц, применяющих её по собственной инициативе, т.е. без какого-либо материального стимулирования со стороны?

• 0-10%

Пояснения:

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

Comments on acceptance with external material support: Sand dams require external material support including technical advice to correctly site, design and construct

There is a little trend towards spontaneous adoption of the Technology

Comments on adoption trend: There is some evidence of spontaneous adoption amongst development agencies working in regions suited to sand dams.

6.7 Сильные стороны/ преимущества/ возможности Технологии

Сильные стороны/ преимущества/ возможности по мнению землепользователей
“I will be able to rent a plot of land near to the sand dam and grow vegetables (tomatoes, peppers, and French beans). My animals will also be healthy because they will always be able to drink here, even during the droughts.” Mauwa Maingi, self-help group member, aged 87, 2010
Mbatha Mbuli, 83. "My family collects water from a near-by well, about ½ Km away, but the water is very salty. It takes one hour to collect water, and needs 6 trips to fetch enough to last the day. There is a pipeline nearby but we must pay 2 shillings per 20 litres. I planted 9 different crops last year, but only 2 survived. I wanted to work with Excellent on this project because I had heard that the projects you support help communities like us to build sand dams, grow trees and create seed banks. I would like to grow trees like Neem in the future and a sand dam here will really help with that. Excellent shares in the interests of the community and they listen to the community and take direction from us"
Stephen Hussey, Dabane Trust, 2011 “Dabane has made its name by getting water out of sand rivers – Our next step is to ensure we don’t over abstract – the answer to that, especially upstream, is sand dams. Without a doubt.”
Milka Mutunga, Kilili Catchment SHG, Kenya 2009-10 "The distance that I used to travel in order to fetch water has been reduced..now I am able to plant more vegetables close to my home. I have learnt how to dig terraces which have helped in increasing the yields that I harvest from my farm..If this is not development then I do not know what development means"
Kimanthi Ngovi, Yikiuuku SHG “The sand dams have done an incredible work for us – water availability at a shorter distance has helped me in saving time for other activities. When water was a long way away I had to get time to collect water in one day and dig terraces on the other day. Today I can fetch water and dig terraces on the same day.”

Сильные стороны/ преимущества/ возможности по мнению составителя или других ключевых специалистов
Sand dams provide a safe, reliable, year round, local supply of water for people, crops and livestock in water scarce environments How can they be sustained / enhanced? The very low cost of operating and maintaining sand dams means they are well suited to remote, poorly served regions. Community ownership is critical to their effective management.
Sand dams save farmers hours every day that they can invest in improving their farms to grow more food and create the potential for farmers to irrigate trees and crops, water livestock and generate an income How can they be sustained / enhanced? Don’t build a sand dam in isolation. An independent evaluation in 2010 of 2 sand dam programmes found the long term impacts on poverty, food security and incomes were greatest when sand dams were integrated within a wider community development programme aimed at improving food production, livestock management and land management practice.
Because it is a low cost technology that requires a major community contribution and the knowledge and skills of locally trained artisans, it’s a solution particularly suited to community ownership and self-supply. This contributes to effective implementation. How can they be sustained / enhanced? Don’t short cut community ownership. Communities better understand and are able to implement solutions to their problems if they are central to the planning of the solution. Genuine community commitment and ownership from initial planning to on-going management is vital to realise the intended benefits and full potential created by a dam. Legal registration and agreements to safeguard community access and water rights help this.
Sand dams provide significant environmental benefits such as aquifer recharge, increased downstream flows in the dry-season, rejuvenation of river ecologies and moderation of floods. As such, it contributes to eco-system services and climate change adaption. How can they be sustained / enhanced? Support terracing, tree planting and conservation farming in the wider catchment. This conserves soil and water on farms, increases aquifer recharge and base flows into the dam and reduces the amount of silt in the sand dam aquiver. Research and disseminate evidence of these benefits and the value of these eco-system services
The technology is scaleable and has a broader application for use as a rural and game park road crossing to replace less effective culvert bridges. How can they be sustained / enhanced? In order to upscale this solution, there is a need for greater awareness and advocacy of the technology and its benefits amongst these groups. Nothing generates interest in sand dams more than exposure to successful examples

6.8 Слабые стороны/ недостатки/ риски Технологии и пути их преодоления

Слабые стороны/ недостатки/ риски по мнению составителя или ответственных специалистов	Возможные пути их преодоления/снижения?
Although sand dams are technically replicable, their application in new contexts requires careful understanding and consideration.	Excellent Development has developed a framework tool to help agencies identify the political, economic, social, technical, legal and environmental factors that should be taken account of when introducing sand dams to a new context.
Sand dams require the technical knowledge and skills of local artisans in order to correctly site, design and construct them	The technical barriers to adoption are low: The technical skills required have and can be developed locally. Learning exchanges between implementing organisations and developing technical manuals and resources aids this learning
This is a drylands solution. Sand dams can only be built on seasonal rivers with sufficient sandy sediment and where the bedrock or impermeable layer is accessible in the river bed.	Increase awareness of the criteria that determine the technical suitability of a site. Use simple field tests, such as sediment seiving and probing, to assess potential sites and to map the potenial application of sand dams.

7.1 Методы сбора/ источники информации

7.2 Ссылки на опубликованные материалы

Название, автор, год публикации, ISBN:

Be buffered website including Managing the Water Buffer for Development and Climate Change Adaptation. Groundwater recharge, retention, reuse and rainwater storage. Steenbergen F. van and A. Tuinhof. (2009) which includes sand dams

Где опубликовано? Стоимость?

www.bebuffered.com/3rbook