The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
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The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
General catchment characteristics • 600 km2 wide • Elevations ranging from approximately 1400 m asl to 0 m asl. • Precipitation ranges from 700 to 1100 mm/y on average,( from the coast to the Apennines divide. )
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
General catchment characteristics Flow duration curve assessments
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Main channel characteristics
wide gravel bed where braided sub-channels form and evolve continuously gravel has been extracted in large quantities (stopped in 1980)
•
Channel erosion (Canyon)
•
hydrogeological risks due to the presence of infrastructures
•
reduced the solid discharges to the coast
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Area of interest Direction of regressive scour
Flow direction
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Position of the problem Drop of approximately 15 m in the plain( natural channel slope is already of the order of 0.1 – 1 %. )
regressive scour Rapidly evolved in the last 15 years 1990-2004
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Position of the problem 41
XSection 42
42
1990 2004 XSection 41
10 m
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Water diversion as a tool for channel stabilization
diverting a significant part of the flows
HYDROPOWER PRODUCTION
reducing transport capacity of the stream AND the scouring pace over extended time periods
maximise effects of transport capacity reduction AND good profitability of energy production
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Hydraulic –Transport modeling
natural flow duration curve
hydraulic – transport model of the river
modifications according to different withdrawal hypotheses quasi-2D hydraulic model (HEC-RAS) wide combination of approaches for the estimation of sediment transport capacity
optimal withdrawal potentiality of approximately 8 m3/s The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Hydraulic – Transport modeling marecchia_river
Plan: Plan 18
28/09/2005 marecchia_river
.04
. .03 0 3 5
105
.1
Plan: Plan 17
20/09/2005
.04 .04
Legend
.07
.04 .03
.07
.1
.04
130
Legend
Ground Ground
Bank Sta
Bank Sta
100
120
90
Elevation (m)
Elevation (m)
95
110
85
80
100
75
90
70
0
200
400
600
800
1000
1200
0
200
400
600
800
1000
Station (m)
Station (m)
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
1200
Hydraulic – Transport modeling Transport in suspension
Transport at the channel bottom
Meyer-Peter e Mueller (1948)
Smith e McLean (1977)
Ashida e Michiue (1972)
Van Rijn (1984)
Engelund e Fredsoe (1976, 1982)
Garcia e Parker (1991)
Van Rijn (1984) Parker (1991)
•D50 =0.1 mm mean representative diameter
•Different withdrawals hypothesis
Flow shear stress duration curves –Transport capacity The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Hydraulic – Transport modeling 50 2] τ [N/m 45
Shear stress τ =N/m2
Flow shear stress duration curves
40
35 ante Qder=1
30
Qder=3
Ante operam condition
Qder=5
25
Qder=8
Different derived discharge
Qder=10 Qder=15
20
15
10
5
0 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Q
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
100%
Hydraulic – Transport modeling 60%
% reduction in transport capacity on the yearly basis for bottom and suspended transport
50%
40%
bottom rid sosp suspend
Design discharge of 7.4 m3/s
rid fondo
30%
20%
10%
Qder ranging from 1 to 15 m3/s 0% 0
2
4
6
8
10
12
14 Q der [m3/s] 16
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Evaluation of Hydropower development feasibility • Total hydraulic drop 20 m • Kaplan turbine (maximum discharge of 7.4 m3/s) •Annual average discharge 3.7 m3/s •Minimum ecological flow 0.7 m3/s •Annual discharge to turbines 92 Mm3/y
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Evaluation of Hydropower development feasibility
•Mean annual energy production 3369 MWh •CO2 equivalents 1955 t/y •Investment Pay back period under 3 years •Internal rate of return (IRR) = 39.6 % •Net Present Value (NPV) over 30 yrs of about 1,700,000 Eur (public incentive to small hydropower plants )
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Evaluation of Hydropower development feasibility
Discharge withdrawal
and Riverine habitat modification ???
•Withdrawal affects only a short stretch of the river, approximately 1000 m • The stretch under consideration is already virtually impermeable to fish migration
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
Conclusions Carefully designed small hydropower plant can be thought of as a multi-objective tool for river management
water withdrawal as a means of scour control
profitability of the plant allows to envisage hydropower development as a strategy to generate funding for river restoration besides
coupling the hydrologic, hydraulic and ecologic understanding of rivers with clean energy production may enhance our capabilities to detect situations where hydropower development is not only sustainable, but also helps a general management of river systems. The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development
www.gecosistema.it
The Marecchia jump power project: coupling hydrogeologic hazard mitigation with hydropower development