Progress zero flow in Ruaha River at Mtera virtual station progressing with last sections of standingsurface water (dark blue) drying on September 30, 2021. (L2A Sentinel 2)
Continued drying of surface flow and visible flow in sediments riverbed (greyish) on September 15, 2021
Zero Flow Ruaha at Mtera on September 5, 2021 (S2A Sentinel 2, B08, B04, B03, near infrared)
Zero Flow Ruaha at Mtera on August 31, 2021. Compare first Zero Flow event 2020 with first Zero Flow Event 2021 (2nd Alert) just before the confluence with the Little Ruaha at Mtera.
Near zero flow closing in, on August 21, 2021. Compare left image below (first zero flow event 2020). Click on image enlarge.
Compare 2nd Alert or first zero flow in Ruaha at Mtera Reservoir on September 15 2020 (left image) , with status on August 16, 2021. Near zero flow (2nd Alert) for 2021 (right image) is predicted within a few days.
Zero Flow in Ruaha at Mtera (Alert 2) nearing on August 11, 2021
Compare Zero Flow Ruaha at Mtera on September 15, 2020 with status flow on same location on August 6, 2021.
Compare flow at virtual zero flow station on August 1, 2021 (left) and 3.4km upstream in Ruaha at Mtera Reservoir on the same date. The Sentinel 2 (L2A) image has 5m resolution
Compare flow at virtual zero flow station on July 27, 2021 (left) and 3.4km upstream in Ruaha at Mtera Reservoir on the same date. The Sentinel 2 image has 5m resolution.
Less than 1 month before ZF in Ruaha at Mtera on virtual zero flow station 2020, date image July 27, 2021
Less than 4 weeks predicted (First Alert Phase) before zero flow Ruaha at Mtera Reservoir on July 17, 2021. Monitored location is 3.4km upstream of the virtual zero flow station at Mtera for 2020.
Sentinel-2 July 17, 2021 (10m) compare with Landsat (30m) below of day earlier – click image to enlarge.
Landsat 8 (30m pixels) on July 16, 2021 at section with early zero flow in Ruaha River a few kilometers from Mtera Reservoir.
Landsat 8, image on July 16, 2021 – 30m pixels make conclusive zero flow observations difficult, see Sentinel-2 (10m) image below 4 days earlier
Cloud covers 2020 zero flow location downstream a second location is checked on July 12, 2021 in the Ruaha at Mtera Reservoir.
On July 7, 2021, Water Level in Ruaha River at Mtra Reservoirs still higher than one month before 2020 first zero flow event (see below)
Flow Level at Early Zero Flow section of the Ruaha at the Mtera Reservoir is declining on July 2, 2021 compared to the level 10 days earlier on June 27, 2021 (see image below). But still well above the one month water level before the zero flow in 2021 the image of September 15, 2020 below.
Enlarged water level on June 27 2021, zero flow section Ruaha River at Mtera.
Compare the flow in the Ruaha some kilometers upstream of the Mtera Reservoir on June 27, 2021 with the next image one month before the first zero flow event at Mtera on August 16, 2020
Enlarged water level one month before zero flow in 2020, image of August 16.
One month before (August 16, 2020) the first Zero Flow event observation in Ruaha at Mtera reservoir on September 15 2020.
Ruaha Zero-Flow period ended water reaches Mtera Reservoir (zero flow Sep 15, 2020 – Jan 3, 2021)
On January 8, 2021 sediment laden water from the Little Ruaha from center bottom of image and the Ruaha from center left of the image, fill the Mtera Reservoir. The width of the image represents 15km. (click on image to enlarge)
Fifteen kilometers upstream of Mtera Inflow virtual station a glimpse of the Ruaha River reveals in an opening between the clouds the sediment loaded water reaching Mtera on January 3, 2021. The same section is shown on January 8, 2021. (click to enlarge image).
Zero Flow in Ruaha at entrance Mtera Reservoir on December 14, 2020 since September 15, 2020. All wet subsurface flow patches have become dry sand with probably a subsurface trickle deeper in the riverbed.
Upstream sections also start drying with sections of subsurface flow on October 25, 2020. (click image to enlarge)
Greyish subsurface flow patches of riverbed on October 5, 2020. The image is a 10m pixel Color Infrared composite with Band 08, Band 04 and Band 03. (click to enlarge)
The location identified for the first zero flow event nelarged by the magnifier on September 25, 2020.
Zero Flow to Mtera on September 25, 2020. Verify the located section on image below. (click to enlarge) or compare with same image with magnifier above.
For comparison the same section of the Ruaha is shown with flooding river on January 18, 2021. Each pixels represents 5m. True Color water with high sediment load.
Based on the 5m pixels image the first zero flow event in the Ruaha is assessed on September 15, 2020. (enlarge image to verify). The river section is some 2.5m from the reservoir at Mtera.
August 21, 2020 sustained inflow in Mtera Reservoir. (B08, B04, B03)
On August 16, 2020 the Ruaha River with hardly any drainage water from Usangu Rice Fields still supplying Mtera Reservoir. (B08, B04, B03)
Flow into Mtera Reservoir on August 11, 2020. Bush fire smoke lights up red vegetation. (Sentinel-2, Color Infrared, B08, B04, B02)
Ruaha status flow: Flow into Mtera Reservoir on August 6, 2020. (click on image to enlarge)