Status of River Breakages Shabelle March 2019
|SOM_WATER_SHABELLE_RIVER BREAKAGES_SWALIM_032019.pdf||2.25 MB|
|River Breakages_Shabelle_Mar_2019-tabular_data.pdf||420.34 KB|
|Legend of River Breakage Points_Mar_2019.pdf||355.42 KB|
Following a poor rainfall season of Deyr 2018 (Oct – Dec) within the Juba and Shabelle river basins the river flows of the two rivers have since been significantly below normal. Reports indicate of drying river beds in some section of the Shabelle River during the month of February 2019. The situation is expected to improve in April given the GU 2019 rainfall forecast which calls for good rains within the catchments. FAO through SWALIM, has been involved in analysing and mapping the river breakages along the Shabelle River using very high resolution (sub meter) satellite imagery and a Digital Elevation Model (DEM) derived from earlier acquired aerial photographs having 3 meter resolution. Five types of breakages have been identified along Shabelle River namely; Open, Overflow, Potential Overflows, Potential breakages and Closed. The open breakages are those that were still open according to the latest satellite image analysed . The Overflow, indicates points where there has been recent river spillage causing extensive flooding. The potential overflows are those points that have high likelihood of overbank spillage but not overflowing at the time of analysis due to low river flows. The Potential breakages represent points that have very weak river embankments or have experienced several breakages in the past. The closed breakages are those that were previously open but efforts have been made to close them either with sand bags or heavy machinery. A total of 88 Open points have been identified, 44 on each river. In addition, 14 overflow points have been identified along the Shabelle River and none along the Juba River. More overflows could be expected when rivers level rises above normal rate. Several other points, which are either potential or temporarily closed with sandbags, have also been identified. With the Gu rains expected in April 2019, river levels will increase with a likelihood of flooding especially where open and overflow points have been identified. There is therefore an immediate need to close the open points and reinforce areas where there are weak river embankments. Temporary measures can be taken before the season begins. Maps of the status of river breakages along the two rivers, with detailed information, have been produced at large scale and hardcopies can be obtained from FAO SWALIM offices. This information is also available on the SWALIM website. It is worth noting that the methodology is biased towards Remote Sensing (RS) interpretation with only limited “ground truthing” due to access constraints. Open breakages and overflows might have been omitted or classified as potential in some cases where satellite images were not available or may not have been very clear due to heavy cloud cover and dense vegetation cover.
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