Rapic Flood Assessment

Dam Category and Flood Assessment

Dam Category:
A
B
C
D

Flood Assessment:
Safety Flood Check
Design Flood

Duration of Flood:
Safety Check:
Design Flood:

Dam Geometry

Dam Type:
Rockfill
Earthfill
Concrete
Masonry

Top of Dam Level:
Nominal
Measured Low Point
Measured Typical Point
Value for Calculation

Core Level:
Nominal
Measured
Value for Calculation

Slopes:
U/S Slope 1V H D/S Slope 1V H (optional)

Wave Wall Top Level:
Nominal Measured (max) Details of Gaps etc. Base of Wall Level
Value for Calculation

U/S & D/S Protection

Dam Crest protection:
Grass
Tarmacadam
Other

Downstream Dam Protection:
Grass
Reinforced grass
Other

Protection Level Provided:
Allowable Mean Overtopping Discharge q (l/s/m):

Upstream Dam Protection:
Concrete, asphalt, closed concrete block, grass One-quarter of stone setting 10cm higher
Fitted basalt blacks Small blocks over 1/25 of surface Rock armour in one layer on a low permeability base
Open stone asphalt Small blocks over 1/9 of surface Rock armour in two layer on a low permeability base
Open Concrete revetment block

Coefficient, Yf:

Spillway Structure

Spillway Crest/Invert Level:
Nominal
Measured
Lowest Value for Calcs
Spillway Crest Level = TWL
Top Water Level(TWL)

Spillway Pipe Dia/Crest Length:
Nominal
Measured
Lowest Value for Calcs

Catchment Data

Catchment Area Km2
Reservoir Area m2
Mainstream Lenght m
H10 m
H85 m
SAAR mm

Nature of Catchment:
Mountainous
Hilly
Undulating
Flat
Catchment Coeff.k=

Wave Surcharge

Fetch. F m
U50 m/s
Angle of the North *N
Return period: Year

Sloping face with small vertical Wave Wall
Sloping face (no Wave Wall)
Vertical and steep Wave Wall
Angle of the Wave Wall *N

Wave Surcharge 2

Sloping face with small vertical wall
Sloping face (no wall)
Vertical and steep wall

Top of wave wall m
Base of wave wall m
Lower level on wave wall m
Top Water Level (TWL) m

Safety Check Flood Condition

Stillwater level m
Rc m

Lm m
α U/S *
Σ m-1.0
yb
yf
yβ
α wall *
Yv

qmean m³/s/m
l/s/m

qmax m³/s/m
l/s/m

Design Flood Condition

Stillwater level m
Rc m

Lm m
α U/S *
Σ m-1.0
yb
yf
yβ
α wall *
Yv

qmean m³/s/m
l/s/m

qmax m³/s/m
l/s/m

Dam Category and Flood Assessment

Dam Geometry

U/S & D/S Protection

Spillway Structure

Catchment Data

Wave Surcharge

Catchment

Catchment - Rainfall Data:

Stillwater Rise

Stillwater Flood Rise:

Wave Surcharge 1

Wave Height:

Wave Surcharge 2

Safety Check Flood Condition

Design Flood Condition

Conclusion

Check provision of adequate dam freeboard:

Safety Check Flood Condition

Design Flood Condition

Check retention of flood surcharge below top of dam level and core:

Safety Check Flood Condition

Design Flood Condition