The Zero Flow event dates are listed for the Ruaha River Sections next to the magnified remote sensing stations below. The basemap can be viewed here. The related satellite images are grouped per Ruaha River Section with the most recent images on top. The first zero flow event which occurs at the Mtera Reservoir section of the Ruaha River, can be found found at the bottom of this post.
For low/zero-flow analysis of other years, please follow the link.
Label
Ruaha Section Location
Observation/ 1st Occurrence Zero Flow (ZF)
three km. upstream of 1st zero flow monitor section
Few kilometers u/s of confluence Great and Little Ruaha
Ruaha 40km 40km downstream of N’giriama Sill (Ihefu)
December 04, 2021
N’giriama (Ihefu Swamp)
December 09, 2021
Ruaha River Section Confluence Mbarali/Ruaha Branch – Ihefu Entry
December 22, 2021 (gap satellite images flow on Dec 17 – Zero Flow Dec 22, 2021)
Confluence Mbarali/Ruaha Branch
December 17, 2021
Kapunga Rice Scheme Irrigation
From October 23, 2021 and during zero flow period at Park HQ
New NAFCO Headworks diversion low flow Mbarali
December 17, 2021 (all flow)
Return Flow Ruaha River
around (clouds) January 20, 2022
Diversion and Spill Ruaha Rice Fields at Alert 3 and at the time the drainage stopped
On the day of Alert 3 (November 2, 2021) the irrigation and spill is expressed together with the water evapotranspiration of the riverine vegetation. The total water evaporation/ evapotranspiration area using water from the Ruaha including the Chimala irrigation at the bottom left is some 2,543 ha.
Confluence Mbarali and Ruaha River Branches
Zero Drainage in the Ruaha Branch at the confluence with the Mbarali Branch already dry on December 17, 2021. The section of the Ruaha is 650m upstream of the confluence. Compare with high resolution image below (Click image to enlarge)The flow status on the high resolution image of the same section with almost zero drainage in the Ruaha which flows from the bottom left to the right, is comparable to the flow status on December 17, 2021 as captured by the 10m/px Sentinel (NIR) image .Zero Drainage from Mbarali River on December 12, 2021 some 1.75km upstream of the confluence with the Ruaha Branch.
Drainage Critical Flows and Zero Drainage
Zero Drainage at Nyaluhanga Gauge Station on December 22, 2021. The exposed riverbed is clearly visible at two sections. Click to enlarge and scale at upper left of the image. Alert 3 – Drainage drops under critical level at Nyaluhanga Gauge Station on October 28, in 2021 which is 16 days before zero flow at Msembe zero flow.
Zero Overflow N’giriama Sill (Ihefu Swamp)
The first observation of (Near) Zero Overflow from Ihefu Swamp on December 9, 2021 (NIR)Isolated Pools downstream (30km) connected by subsurface flow from the last overflow of the Ihefu Swamp on December 4, 2021 (NIR)
Msembe Bridge Park Headquarter
Zero Flow at Msembe Bridge on November 14, 2021.
Recession Outflow Park
On November 19, 2021 the Ruaha Riverbed still shows signs of subsurface flow and a singe pool. Forty kilometers downstream (as the bird flies) from the Park Headquarter.
Mtera Reservoir
First Occurrence Zero Flow at Mtera VDAS on August 31, 2021
Alert One, 1 month before predicted ZF at Mtera
Due to poor prediction of the IMERG sum of monthly Rains in 2021, a visual prediction (RS) based on the 2020 Alert One was applied. The flow status of the Ruaha River at Mtera comparable to the 2020 Alert 1 flow status is observed on July 17, 2021 on which date Alert One for 2022 is declared.
