Date post: | 23-Oct-2015 |
Category: |
Documents |
Upload: | octatheweel |
View: | 73 times |
Download: | 10 times |
57
8. IRRIGATION BARRAGES
8.1 Background
The ten barrages on the Shabelle and Juba Rivers are probably the most significant pieces of irrigation infrastructure in Somalia. They were constructed to increase the water depth in the river and divert the flow for irrigation purposes. The barrages were built of concrete with mechanical, metal gate structures, which can be opened during flood times. In Somalia, irrigation barrages were developed in the middle and lower parts of the two rivers from as early as the 1920s to irrigate land for commercial and food crops. Good topography permitted gravity irrigation through a network of canals. A total of nine barrages were built on the Shabelle River, and one on the Juba River. Their locations are given in Figure 8.1.
Apart from a few areas where rain-fed agriculture is practiced, Somalia depends largely on irrigated agriculture to feed her people. The bulk of the irrigated agriculture is practiced along the riverine areas of the Juba and Shabelle Rivers through gravity flow. Barrages play a big role in controlling water off-take of the main (primary) canals, which subsequently connect to secondary and tertiary canals that irrigate the farms. Unfortunately the barrages and other irrigation infrastructure, started to deteriorate in the early 1990s after the fall of the central Government (SWALIM Technical Report No W-05). To improve on irrigated agriculture there is need for rehabilitation of these barrages, primary canals and other related infrastructure. Details about individual barrages, including the current status, are summarised below.
Figure 8.1: Map of geographical location of barrages and irrigation schemes
58
8.2 Details of individual barrages
8.2.1 Sabuun barrage
Area around Sabuun barrage from 2008 aerial photos
Brief history
Established in 1970’s by the Somali Government in Sabuun village, Jowhar District - Middle Shabelle Region to regulate supply of irrigation water and to protect irrigated lands from flooding. There are seven gates fitted to the barrage, which regulate the water level through manual lifting gear.
Command area 50 942 haIrrigation schemes served
Jowhar sugar cane scheme
Primary canals FAO/Duduble Canal that feeds the Jowhar Off Stream Storage Reservoir
Last intervention Barrage gates and canal intake rehabilitated in 2006-2008.
Current statusBarrage structure is in good condition; however, the main canal is silted and overgrown by trees and vegetation.
Intervention requirements
Canal desiltation and headwater regulator rehabilitation
Table 8.1: Summary details about Sabuun barrage
Intake to FAO canal under rehabilitation in 2008 Sabuun barrage as of 2008
Figure 8.2: Sabuun barrage and associated canals
59
8.2.2 Balcad barrage
Brief historyEstablished in 1967, in Balcad District – Middle Shabelle Region, to regulate river levels and reduce flooding downstream. The barrage has 12 gates fitted with manual lifting gear.
Command area 10 000 haIrrigation schemes served
Balcad cotton project
Primary canals Yaaqlow / Mashruuca
Last interventionNot in SWALIM’s records; however field reports indicate that recent work has been done on the barrage by individuals.
Current status ReasonableIntervention requirements
Mechanical rehabilitation of barrage; civil works on river channel; canal desiltation, etc.
Table 8.2: Summary details about Balcad barrage
Area around Balcad barrage from 2008 aerial photos
Figure 8.3: Balcad barrage and associated canals
Silted canal taking off Balcad barrage Balcad barrage 2010
60
8.2.3 Janaale barrage
Area around Janaale barrage from 2008 aerial photos
Brief history
Established in 1927, in Qoryooley District – Lower Shabelle Region, to divert water into canals and regulate river levels to reduce flooding downstream. In all barrages in the Lower Shabelle Region, this is the major barrage, whereby the operation of the other six downstream barrages depends on it. The barrage is fitted with 11 gates that utilise manual lifting gears.
Command area 67 440 haIrrigation schemes served
The Janaale Buulo Mareerta irrigation schemes
Primary canals Primo Secondario, Asayle and Dhame Yasin canals. There are also a number of upstream direct intake canals that depend on the barrage too.
Last intervention Desiltation of primary canals in 2009
Current statusPoor – engineering design works are ready for rehabilitation of barrage in late 2011 / early 2012. This will include replacement of all gates and gears as well as barrage superstructure.
Intervention requirements
Replacement of barrage gates, lifting gears and barrage super structure; erosion control downstream
Table 8.3: Summary details about Janaale barrage
Broken Janaale barrage gate bracket in 2009Janaale barrage as of 2009
Figure 8.4: Janaale barrage and associated canals
61
8.2.4 Mashallaay barrage
Area around Mashallaay barrage from 2008 aerial photos
Brief history
Established in 1986, in Qoryooley District to regulate river levels and provide additional water for irrigation through Primo Secondario canal. Barrage fitted with 8 gates. Lifting mechanism composed of a lifting gear and electric motor. The barrage has never functioned due to faulty link canal design (water flow was in opposite direction, from Primo Secondario to the Shabelle River).
Command area 27 000 haIrrigation schemes served
The Janaale Buulo Mareerta irrigation schemes
Primary canals Link canal – that feed into the Primo Secondario canalLast intervention NoneCurrent status Very good barrage structure, poor gates and lifting gearsIntervention requirements
Re-design of barrage to raise water level upstream; desiltation of canals
Table 8.4: Summary details about Mashallaay barrage
Mashallaay barrage in 2007 Canal intake at Mashallaay barrage in 2007
Figure 8.5: Mashallaay barrage and associated canals
62
8.2.5 Qoryooley barrage
Area around Qoyooley barrage from 2008 aerial photos
Brief history
Established in 1955, in Qoryooley District – Lower Shabelle Region, to regulate river levels and divert water to Fomari (Wadajir) and Libaan canals. The barrage was fitted with a manual lifting gear with turning wheels.
Command area 4 120 haIrrigation schemes served
Janaale Buulo Mareerta irrigation schemes
Primary canals Libaan and FarhanoLast intervention New lifting gears fitted in 2009Current status GoodIntervention requirements
Erosion protection downstream of barrage; desiltation of river upstream of barrage
Table 8.5: Summary details about Qoryooley barrage
Qoryooley barrage before rehabilitation Qoryooley barrage in 2009 after rehabilitation
Figure 8.6: Qoryooley barrage and associated canals
63
8.2.6 Falkeerow barrage
Area around Falkeerow barrage from 2008 aerial photos
Brief history
Established in 1955 by the Italian Government, in Qoryooley District – Lower Shabelle Region, to regulate the river levels and divert water into Furuqulay, Bakooro and other canals for irrigation. The barrage has 9 gates lifted manually using a lifting gear.
Command area 26 800 haIrrigation schemes served
The Janaale Bulo Mareta irrigation schemes
Primary canals Furuqulay and Bakooro canals
Last interventionErosion protection and replacement of lifting gears and general service of gates in 2009
Current status GoodIntervention requirements
Additional mechanical works; desiltation of canals and additional river erosion protection downstream the barrage.
Table 8.6: Summary details about Falkeerow barrage
Falkeerow barrage before rehabilitation
Figure 8.7: Falkeerow barrage and associated canals
Falkeerow barrage after 2009 rehabilitation (civil works)
64
8.2.7 Kurtunwaarey barrage
Area around Kurtunwarey barrage from 2008 aerial photos
Brief history
Established in 1986 by the Somali Government, in Kurtunwaarey District – Lower Shabelle Region to abstract water through canals to support irrigation of farms for drought displaced population. It has 8 gates, and the lifting mechanism comprise of mounted slides on steel structures.
Command area 5 000 haIrrigation schemes served
Kurtunwaarey settlement scheme
Primary canals Towfiiq, Hagaag, Shanad, SadixadLast intervention Replacement of gates and lifting gear; river desiltation in 2009 Current status Operational and in good conditionIntervention requirements
Erosion protection of river downstream of barrage
Table 8.7: Summary details about Kurtunwaarey barrage
Kurtunwaarey barrage before rehabilitation
Kurtunwaarey barrage after the 2009 rehabilitation
Figure 8.8: Kurtunwaarey barrage and associated canals
65
8.2.8 Sablaale barrage
Area around Sablaale barrage from 2008 aerial photos
Brief history
Established in 1987 by the Somali Government, in Sablaale District – Lower Shabelle Region, to divert water into Sablaale irrigation settlement scheme. It has a single main gate with a manual lifting gear and 4 weirs.
Command area 940 haIrrigation schemes served
Farjano / Sablaale settlement scheme
Primary canals Several small canalsLast intervention None
Current statusStructure in good condition; canals in poor condition; access road broken and river meanders bringing little/no water during the dry season.
Intervention requirements
Replacement of lifting gear and gates; repair of access road and river desilting and alignment
Table 8.8: Summary details about Sablaale barrage
Broken access road to Sablaale barrage in 2007 Sablaale barrage structure in 2007
Figure 8.9: Sablaale barrage and associated canals
66
8.2.9 Hawaay barrage
Area around Hawaay barrage from 2008 aerial photos
Brief history
Established in 1926 by the Italian Government, in Baraawe District – Lower Shabelle Region, to divert water into Hawaay Irrigation scheme and to serve small canals irrigating farms neighbouring the River Shabelle. It has 1 slide main gate and a number of sluice gates.
Command area 3 000 haIrrigation schemes served
Hawaay irrigation settlement
Primary canals Several small canalsLast intervention NoneCurrent status Very poor, with structural problems; river changed courseIntervention requirements
The whole structure needs replacement, aligning of river channel and desiltation of all irrigation water canals
Table 8.9: Summary details about Hawaay barrage
Hawaay barrage in 2007 Canal intake at Hawaay barrage in 2007
Figure 8.10: Hawaay barrage and associated canals
67
8.2.10 Fanoole barrage
Area around Fanoole barrage from 2008 aerial photos
Brief historyEstablished in 1977 to divert flow of water to be used mainly for irrigation in the Fanoole rice irrigation scheme in Jilib District - Middle Juba Region.
Command area 15 250 ha
Irrigation schemes served
Fanoole rice irrigation scheme
Primary canals Several small to medium canals
Last intervention None
Current statusGood structure, but river changed course leaving the barrage hanging on the river side
Intervention requirements
Aligning river; mechanical and structural investigations required to guide rehabilitation works.
Table 8.10: Summary details about Fanoole barrage
Closer view of Fanoole
Figure 8.11: Fanoole barrage