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Re-optimization and
reoperation study of the
Akosombo and Kpong dams
Dr Marloes Mul
Thor Windham-Wright
RE-OPTIMIZATION AND REOPERATION
Improving livelihood of people living downstream of
Akosombo and Kpong that were affected ...
RESTORATION HYDROGRAPH WORKSHOP
• Objectives
– Establish flow targets for Akosombo and Kpong dams
• Establish flow targets...
CONSTRUCTING HYDROGRAPHUser
groups/is
sues
Step 1 Step 2 Step 3
From interviews and data, form
“ideal” hydrographs for var...
ESTABLISHING FLOW TARGETS
sues From interviews and data, form
“ideal” hydrographs for various
ecological and agricultural ...
ESTABLISHING FLOW TARGETS
• Hydrology based approach (using Global Environmental Flow
Calculator)
ESTABLISHING FLOW TARGETS
PRE- AND POST DAM ACTIVITIES
Pre-dam
Post-dam
ESTABLISHING FLOW TARGETS
• Expert opinion (examples)
– Estimating water demands (Discharge, [m3/s])
• Domestic water use
...
ESTABLISHING FLOW TARGETS
• Expert opinion (examples)
– Low flow requirements (Saltwater intrusion length [m])
• Clams
• B...
ESTABLISHING FLOW TARGETS (DAY 2)
• Combining individual flow targets
into restoration hydrographs
– Prioritization/ scori...
ESTABLISHING FLOW TARGETS (DAY 2)
• Combining individual flow targets
into restoration hydrographs
– Identifying key targe...
ESTABLISHING FLOW TARGETS (DAY 2)
• Estimating ecosystems response
to selected restoration flow
hydrographs
– Quantitative...
PROGRAMME DAY 1
time topic institution
DAY 1 Establishing environmental requirements per each sector
8:30-8:40 Welcome and...
PROGRAMME DAY 2
DAY 2 Constructing restoration hydrographs
8:30-8:40 Welcome back WRC Ben Ampomah & Eric Ofosu
8:40-9:00 P...
Thank you for your attention
Thor Windham-Wright
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Re-optimization and reoperation study of the Akosombo and Kpong dams (Ghana) - Restoration Hydrograph Workshop

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Presented by IWMI researcher, Marloes Mul, on the Re-optimization and reoperation study of the Akosombo and Kpong dams - Ghana, August 2015. Presented during a stakeholder a workshop held in Accra to explore the potential positive and negative impacts of changing flows.

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Re-optimization and reoperation study of the Akosombo and Kpong dams (Ghana) - Restoration Hydrograph Workshop

  1. 1. Re-optimization and reoperation study of the Akosombo and Kpong dams Dr Marloes Mul Thor Windham-Wright
  2. 2. RE-OPTIMIZATION AND REOPERATION Improving livelihood of people living downstream of Akosombo and Kpong that were affected by construction of the two dams through: • Re-operating dams – Releasing flows to improve ecosystems downstream – Considering impact on downstream developments in the floodplains – While increasing hydropower production (hypothesis) • Supporting downstream livelihoods Q2: What will be the impact of releasing these flow requirements on - Infrastructural developments in the floodplains affected by releasing flood peaks - Intakes affected by increased saltwater intrusion - …  Feasible operation scenarios
  3. 3. RESTORATION HYDROGRAPH WORKSHOP • Objectives – Establish flow targets for Akosombo and Kpong dams • Establish flow targets for different components – Fisheries – Aquatic weeds – Agriculture – Health – Groundwater – Sediments • Combine targets into flow scenarios
  4. 4. CONSTRUCTING HYDROGRAPHUser groups/is sues Step 1 Step 2 Step 3 From interviews and data, form “ideal” hydrographs for various ecological and agricultural processes Combine to form “signature” hydrograph for each user group/issue Combine to form “overall” monthly “ideal restoration” hydrograph with monthly ranges – overlay historical and current hydrographs and physical limits (dashed lines) imposed by dam/hydro structures and electric power base load etc. Fish Weeds Clams Disease Agriculture Structures
  5. 5. ESTABLISHING FLOW TARGETS sues From interviews and data, form “ideal” hydrographs for various ecological and agricultural processes Combine to “signature” each user g Fish Weeds Clams Disease Agriculture Structures • Examples – Hydrology-based • Percentage of flow • Minimum flow requirement – Field based experiments • Detailed fieldwork – Expert opinion • Comparison of pre- and post dam situations • Using proxies to estimate responses
  6. 6. ESTABLISHING FLOW TARGETS • Hydrology based approach (using Global Environmental Flow Calculator)
  7. 7. ESTABLISHING FLOW TARGETS PRE- AND POST DAM ACTIVITIES Pre-dam Post-dam
  8. 8. ESTABLISHING FLOW TARGETS • Expert opinion (examples) – Estimating water demands (Discharge, [m3/s]) • Domestic water use • Irrigation water requirements – Flood requirements (Location, Water level/ peak [m], Duration) • Spawning grounds • Flood recession agriculture – Flow velocity ([m/s]) • Flushing aquatic weeds • Sediment transport (unblocking sand bar, flushing sediments into the sea)
  9. 9. ESTABLISHING FLOW TARGETS • Expert opinion (examples) – Low flow requirements (Saltwater intrusion length [m]) • Clams • Brackish water fish • Intakes for domestic water use • Aquatic weeds – Water level (Location [m]) • Intakes for irrigation • Intakes for domestic water use – Water level fluctuations (Location, Δ[m]) • Bilharzia snails • Aquatic weeds
  10. 10. ESTABLISHING FLOW TARGETS (DAY 2) • Combining individual flow targets into restoration hydrographs – Prioritization/ scoring of different components – Identify targets that are in agreement with each other – Identifying conflicting targets (trade- offs) – Develop 3-5 different scenarios aiming for different objectives (eg irrigation vs fisheries) by dam/hydro structures and electric power base load etc. Fish Weeds Clams Disease Agriculture Structures
  11. 11. ESTABLISHING FLOW TARGETS (DAY 2) • Combining individual flow targets into restoration hydrographs – Identifying key targets for each scenario • Peak flow target • Dry season flow target by dam/hydro structures and electric power base load etc. Fish Weeds Clams Disease Agriculture Structures
  12. 12. ESTABLISHING FLOW TARGETS (DAY 2) • Estimating ecosystems response to selected restoration flow hydrographs – Quantitatively or qualitatively • Absolute values per scenario (fish catch, $ revenue, yield, …) • Relative values (compared to base case, x times) • Qualitative indicators (++, +, +/-, -,--) – Estimating damages/ sectors affected • Prioritization of flow scenarios by dam/hydro structures and electric power base load etc. Fish Weeds Clams Disease Agriculture Structures
  13. 13. PROGRAMME DAY 1 time topic institution DAY 1 Establishing environmental requirements per each sector 8:30-8:40 Welcome and introduction WRC 8:40-9:00 Introduction and scope of the workshop IWMI 9:00-9:30 Outcomes of community consultations Quantification of restoration objectives CAW 9:30-10:30 Fish - River fish - Clams - Aquaculture WRI 10:30-11:00 Coffee break 11:00-12:00 Aquatic weeds WRI 12:00-12:30 Health - Schistosomasiasis - Malaria IESS 12:30-14:00 Lunch 14:00-15:00 Agriculture - Flood recession farming - Irrigation IWMI 15:00-15:30 Groundwater WRI 15:30-16:30 Sediments 16:30-17:00 Conclusion day 1 WRC/IWMI
  14. 14. PROGRAMME DAY 2 DAY 2 Constructing restoration hydrographs 8:30-8:40 Welcome back WRC Ben Ampomah & Eric Ofosu 8:40-9:00 Presentation of selected scenarios for restoration flow IWMI Marloes Mul 9:00-10:40 Discussion of flow scenarios (20min each) - Key targets and indicators - Impact on different sectors Facilitation by IWMI Thor Windham-Wright 10:40-11:00 Coffee break 11:00-12:30 Estimation and quantification of impact per sector per scenario Facilitation by IWMI Thor Windham-Wright 12:30-14:00 Lunch 14:00-15:00 Way forward - Information gaps to be addressed Facilitation by IWMI Thor Windham-Wright 15:00-15:30 Conclusion day 2 WRC/IWMI
  15. 15. Thank you for your attention Thor Windham-Wright

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