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May 8 12 tweets 10 min read Twitter logo Read on Twitter
#KakhovkaReservoir #KakhovkaHPP Status Follow-up: 8 May 2023. Upon further analysis of 6 May 2023 Sentinel-2 imagery and consultation with @tom_bike @Gergyl & @BruckenRuski, we believe the #KakhovkaReservoir water is "over-topping" the #KakhovkaHPP dam. /1
Time-series loop from 27 March 2023 to 6 May 2023. Note the "brightening" downstream (left side) of the #KakhovkaHPP sluice gates last frame in loop which is water flowing over the top of the dam. Over-topping is particularly evident on the 3 northern most sluice gates. /2
Why is this happening? Recall the Russian occupiers blew up the road and rail deck above the #KakhovkaHPP dam sluice gates on 10 NOV 2022 as part of the RF retreat ("strategic repositioning") from the Dnipro right bank. /3
The damage to (removal of) the road and rail deck allowed the right bank (north-side) sluice gates #26-28 to be visible using satellite and drone reconnaissance. This is why the 6 May 2023 Sentinel-2 image shows over-topping of these sluice gate more readily in that section. 4/ ImageImageImageImage
What is the impact to structural integrity of #KakhovkaHPP dam from over-topping? We can't say with certainty, but as long as the water is flowing over the concrete raceways, the dam should be stable. However, persistent water over-topping forces risks damaging the gates. 5/
What should we look for in the near future? Over-topping may continue through the Dnipro spring peak water flow which should last through June 2023. Water which otherwise would be diverted from #KakhovkaReservoir to the Kakhovsky and Dniprorudne Channels is not being diverted. 6/ Image
Russian occupiers have destroyed most of the hydro-technical facilities in occupied Kherson and Zaporizhzhia in addition to disabling #KakhovkaHPP ability to manage water discharge rates by destroying the lock, the HPP turbines, and gantry cranes. 7/
Dnipro river water which would otherwise be diverted or allowed to flow downstream is being retained in the #KakhovkaReservoir thereby raising the water level as a consequence of Russian destruction of water management facilities. 8/ Image
The good news is, for now, #KakhovkaHPP dam is stable with minimal chance of downstream flooding and the #ZaporizhzhiaNPP has sufficient access to water. The risk of catastrophic dam failure remains as long as Russian occupiers control #KakhovkaHPP. 9/
In summary, #KakhovkaHPP water over-topping is occurring and could last through the end of June 2023. We believe risk to the dam integrity is not threatened at this time. 10/
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More from @davidhelms570

May 7
1. Ruschist operation of Kakhovka HPP (K-HPP) dam has been reckless. Kakhovka Reservoir (KR) water level has alternated from record low to record high in just 3 months. Loop (6 FEB-6 MAY 2023) shows sand bars receding with rising KR water. #NAFOWeather🧵
2. These images are of the K-HPP from Left: 6 FEB, and Right: 6 MAY 2023 (enhanced from data included in loop). ImageImage
3. North Crimean Canal intake, Left 20 FEB 2023 Right 6 May 2023: Latest image show water gushing through NCC intake gate at Tavrisk as record KR level is pushing water through gravity fed NCC at high rates. ImageImage
Read 7 tweets
May 6
1. Russians are once again attempting to frighten residents in occupied Kherson and Zaporizhzhia on the left bank of Kakhovka Reservoir into evacuating. This is part of a larger information operation ahead of the Ukrainian offensive. A #NAFOWeather 🧵
2. TASS reported (some western media repeated) that the Kakhovka HPP dam could burst and this would flood Zaporizhzhia NPP and surrounding communities. This is pure rubbish. If the Kakhovka HPP dam burst, Kakhovka Reservoir would dramatically LOWER as these location are upstream. ImageImage
3. Russian propaganda uses facts, often reported by the west, with other false statements to create an environment of fear and uncertainty. It is TRUE Kakhovka Reservoir is at record high levels and the K-HPP controls water discharge for K reservoir.
Read 15 tweets
May 5
1. A backgrounder on how soil moisture changes over time. A #NAFOWeather 🧵
2. Soil moisture is one element of the water balance / hydrologic cycle which includes precipitation, terrain, vegetation state, and atmosphere (temperature, humidity, winds, sunshine/solar radiation). Image
3. Rate of soil moisture changes over time:
Over Weeks to Months - Controlled by vegetation growth
Cite: Reference evapotranspiration in water requirement: Theory, concepts, and methods of estimation, Handbook of Hydroinformatics, 2023
sciencedirect.com/book/978012821… Image
Read 13 tweets
Apr 25
1/ It has been almost a month since I provided a #MudSeason trafficability forecast. My assumption of a "normal" spring rainfall & improving trafficability were way too optimistic as it has rained Every. Damn. Day. since late March 2023. A #NAFOWeather 🧵
2/ #BLUF The trafficability forecast (below) is based on current and predicted rainfall which are well above normal for near the Line of Conflict (LoC). In general, trafficability is delayed about 1 month versus normal. Image
3/ Some input on #MudSeason from authoritative sources: @DefenceHQ "severe mud is highly likely slowing operations vor both sides" but "conditions can be expected to improve in the coming weeks".
Read 17 tweets
Apr 4
1/ Some thoughts on the flooding in Kramatorsk today (4 April 2023).
2/ To be sure, it snowed in Kramatorsk recently, probably 20-25 cm on March 30-31.
3/ For Donetsk Oblast, area-wide precipitation received in the past 10 days was about 35 mm. This puts the most recent 30 day period +16% above normal, but the past 90 days are -16% below normal. Thus, recently precipitation was a nice catch-up from winter precipitation deficit.
Read 6 tweets
Mar 29
1/ Heavy Precipitation/Snowfall *ALERT*
Wednesday Evening (MAR 29) to Friday Morning (MAR 31)
* Heavy snow likely in Luhansk and Donetsk
* Drone operations will be severely restricted
* Trafficability will be severely restricted
* Rising water will make creeks dangerous to ford
2/ 10 Day Forecast of weather for Bakhmut and Kreminna shows rate of precipitation, snowfall, & snow depth Thursday-Friday. Additional rainfall next WED. Most snow will melt by Saturday. Melting snow will make trafficability extremely difficult & rising creeks impassable.
3/ Comparing major global weather models, but agree on extreme precipitation potential next 72 hours (50-75 mm), but position of maxima varies by about 100 km which is relevant to the line of conflict.
Read 8 tweets

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