Application Consultancy: Sand Dam Survey and Design in Carracad Tender, Somalia - 45834748

Procurement Summary

Country : Somalia

Summary : Application Consultancy: Sand Dam Survey and Design in Carracad

Deadline : 29 Sep 2020

Other Information

Notice Type : Tender

TOT Ref.No.: 45834748

Document Ref. No. :

Competition : ICB

Financier : Department For International Development

Purchaser Ownership : -

Tender Value : Refer Document

Purchaser's Detail

Purchaser : CONCERN WORLDWIDE
SOMALILAND
Somalia
Email :procurement.hargeisa@concern.net / haron.emukule@concern.net / paz.lopez@concern.net

Tender Details

Tenders are invited for Application Consultancy: Sand Dam Survey and Design in Carracad.

CONSULTANCY TERMS OF REFERENCE
__________________________________________________________________________

SAND DAM SITE SURVEY AND DESIGN IN CARRACAD

(BORAMA DISTRICT, AWDAL REGION, SOMALILAND)

Project Specifications

1. Background

Concern Worldwide is a non-governmental, international, humanitarian organization dedicated to the reduction of suffering and working towards the ultimate elimination of extreme poverty in the world-s poorest countries.

Concern engages in long-term development work, responds to emergencies, and seeks to address the root causes of poverty through development, education and advocacy work.

Concern Worldwide is a member of the Building Resilient Communities in Somaliland (BRCiS) consortium and is currently implementing the DFID-funded Somaliland Humanitarian and Resilience Programme (SHARP) for the period 2018-2022. The programme goal is to enhance the resilience of vulnerable and marginalized communities to recurrent shocks and stresses and engage in sustainable nutritionally sensitive livelihood strategies.

The BRCiS Consortium-s approach to building resilience has been anchored in 5 main pillars:

1. BRCiS operates in a collaborative and effective manner, identifies innovative programme approaches and ways of working, and utilizes learning to improve programme design and implementation

2. Vulnerable communities have the capacity to withstand shocks through diversified livelihoods, social safety nets and human capital development

3. Youth, women and vulnerable groups have diversified productive livelihoods, protected assets and equitable economic opportunities

4. Communities and local stakeholders have the capacity to mitigate the impacts of future shocks through effective management of natural resources, community integration into local governance, and strong social cohesion

5. Population has improved nutritional status through access to WASH, health and nutrition services, and awareness of good health, nutrition, and hygiene practices

In Borama district (Awdal region), Concern Worldwide and the implementing partner, SOSTA, engaged with five communities in 2019 to lead a vulnerability and risk analysis and a participatory process to prepare Resilience Community Action Plans. The Community Action Plan in Carracad considers enhancing water availability during the dry season through the construction of a second sand storage dam downstream of the current sand storage dam.

A sand dam is a reinforced concrete or rubble stone masonry structure built across the riverbed of a seasonal river to increase the accumulation of coarse sand upstream and enlarge the natural storage capacity of the riverbed aquifer.

Sand dams and sub-surface dams are increasingly recognised as low-cost and robust rainwater harvesting technologies to enhance water availability in drylands and build resilience to the effects of climate change. In 2019, Concern Worldwide supported the MSc research study “An appraisal of the effectiveness and sustainability of sand dams to improve water security and resilience in rural Somaliland”. The study captures best practices and lessons learned from practitioners at regional level and appraises the effectiveness, sustainability and impact of sand dams on water security and resilience through the study of five communities with access to sand dams and sub-surface dams in the regions of Awdal and Woqooyi Galbeed in Somaliland, including Carracad.

This study informs the Concern Worldwide Sand dam pilot project providing preliminary information for the project design.

Project site information Carracad village (10° 4`54.88"N, 43° 4`45.55"E) has an estimated population of 250 households dispersed in the valley and is located approximately 30km NW from the district capital of Borama district (Awdal region). Subsistence rain-fed farming and sale of goat and camel milk are the main livelihood activities in the community. Irrigated farming is marginal.

The seasonal river at Carracad is located in a narrow mountain valley and is formed of coarse sand deposits on top of a layer of white clay. A sand storage dam was built in 2003 and rehabilitated in 2017. It is located in a river section 30m wide, just 100 metres from the community centre (Google Earth map provided in Annex 1).

The dam is made of reinforced concrete covered with a layer of cement. It has a total length of 30.8m with a spillway 23.2m long covering the full width of the riverbed. The right wing wall extends sufficiently into the rocky steep bank but the left wing does not extend sufficiently on the shallow sandy bank, where there is visible signs of water overflow around the wing wall. The crest is 78cm wide and exhibits slight erosion with exposure of the reinforcement bars at the central section. The height of the visible wall is 1m with approximately 50cmextending to the bedrock and keyed 1m below the bedrock. In 2016 the implementing agency repaired the gabions and raised the wall by 20cm, but strong flash floods in 2018 partially washed away the gabions. At the time of the visit in October 2019 the damaged gabions had not been repaired (pictures provided in Annex 2).

The sand sample taken at a depth 30cm in the throwback of the dam showed aheterogeneous composition of gravel, very coarse and coarse sand, medium, fine and very fine sand. In October 2019 sand was saturated with water at depths of 30m. An impermeable while clay layer is located at an approximated depth of 4m.

There are three communal masonry wells in the throwback of the sand dam with estimated depths varying between 4m and 14m. All of them have concrete slabs and a metal cover for manual water lifting. The wells have an average

diameter of 3m and are lined with rocks intercalated by 20mm PVC infiltration
pipes. Communal well #1, closest to the dam wall, is used for domestic
purposes including drinking. The well was dug 4m until reaching a white clay
impermeable layer, however well # 2 has a total depth of 14m and was dug
below the clay layer 9m into the permeable bedrock. Well #2 has a good yield
and is mainly used for livestock watering. Well # 3 is 9m deep but has lower
yield and is occasionally used for livestock and irrigation (pictures and wells
location provided in Annex 2).
Carracad is avery scattered community hence the roundtrip to the wells in the
riverbed vary from 5 to 90 minutes. Additionally, part of the population of
surrounding villages in the valley like Qol Qol and Culacuule also collect water
from the sand dam wells in Carracad as this is the closest water source besides
traditional berkads. There is no restriction on accessing water from the
communal wells, all community members can access water for free and without
quantity limitation. No groups were identified as excluded in the preliminary
study.
The following table summarises the changes perceived by the community after
the construction of the sand dam in 2003:
Dry season water availability
Before: wells provide water 4 months per year (in rainy seasons and
immediately after).
After: wells provide water 9 months per year and dry out during the 3
months of Jilal (January-March).
Net gain: 5 months.
Water used per day in the dry
season
Significantly more because more water is available and for a longer
period.
In the dry season months the quantity of water used remains very limited.
Water expenditure in the dry
season
No fees charged for water before and after the dam.
Frequency of diarrheal
disease
Low frequency of diarrhoeas.
Surface of irrigated land Large increase in the surface of irrigated land upstream of the dams.
Small decrease in water availability for irrigation downstream.
Livestock number and
condition
Large increase in number of households from surrounding villages who
collect water from the wells in Carracad dam.
Many livestock heads were lost with cyclone Sagar in 2018 and numbers
are recovering. Livestock drinking from Carracad wells are in good health
condition.
Livelihoods diversification Home gardening introduced.
Riverine vegetation More vegetation/higher biodiversity upstream of the dam.
Flood risk Less flooding upstream.
More flooding downstream as riverbanks expanded.
Perceived impacts after Carracad dam construction in 2003. Semi-structured group interviews in
Carracad. Concern Worldwide, 2019.
3 | P a g e
According to community interviews the availability of water in Carracad riverbed
increased from 4 months (during rainy seasons and immediately after) to 9
months (April-December), resulting in a remarkable net gain of 5 months local
water supply. Current domestic water use varies from 6-8 jerry cans/HH/day
(23.3 L/p/d) to only 4 jerry cans/HH/day (13.3 L/p/d), below the minimum
SPHERES standard of 15 L/p/d for drinking, cooking and personal hygiene.
The preliminary study shows the estimated maximum extractable water volume
(9, 333 m3) in the sand reservoir, reached at the end of the rainy season, is
theoretically sufficient to cover 100% of the domestic water demand for the
population of Carracad during the long dry season months (estimated at
4, 500m3
considering 20 L/p/d) and 69% of the combined domestic and livestock
demand (Estimated at 13, 500m3
). However, the alluvial aquifer also supplies
water for domestic use and livestock for surrounding villages and demand
exceeds supply in the dry season. As a result, the three wells in Carracad dry-up
during the months of January-March and the population needs to fetch water
from a mountain spring located at 15km.
Carracad
Estimated dam throwback length (m). 1, 000
Maximum width riverbed (m) 35
Maximum depth of sand (m) 4
Dam storage capacity (m3
) 46, 667
Drainable porosity (%) 20%
Estimated maximum volume of extractable water from sand deposit (m3
)
9, 333
Estimated water dema

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