Dams Sector Consequence-Based Top Screen Methodology

3. Impacts on Critical Functions
The failure or disruption of the facility may severely impact essential services or critical
functions that affect populated centers, industrial areas, agricultural regions, flood protected
areas, or inland navigation systems. The CTS questionnaire requires an estimation of the relative
importance (in terms of “size” or “capacity”) of the critical
functions provided by the project. This provides an indirect
measure of the potential indirect impacts and secondary
effects that could be caused by the long-term interruption of
those functions. The CTS questionnaire considers the
following critical functions:
a. Water Supply:
The relative importance of this function is quantified
through the total population served by the facility as the
main water supply source for municipal and industrial use
(M 1 ). Table 4 shows the different ranges considered for this
parameter.
Table 5b: Annual water
b. Irrigation:
deliveries (acre-feet)
The relative importance of this
function is quantified by the value of
annual water deliveries quantified in
dollars or annual volume (M 2 ).
Tables 5a and 5b show the different
ranges considered for this parameter.
c. Hydropower Generation:
The relative importance of this
function is quantified in terms of
total installed capacity (M 3 ). Table
6 shows the different ranges
considered for this parameter.
d. Flood Damage Reduction:
The relative importance of this
function is quantified by the value
of annual flood damages prevented
(M 4 ). Table 7 shows the different
ranges considered for this
parameter.
Annual Water
Level Deliveries (M 2 )
1 M 2 > 6,400,000
2 3,200,000 < M 2 ≤ 6,400,000
3 1,600,000 < M 2 ≤ 3,200,000
4 800,000 < M 2 ≤ 1,600,000
5 400,000 < M 2 ≤ 800,000
6 200,000 < M 2 ≤ 400,000
7 0 < M 2 ≤ 200,000
8 M 2 = 0
Table 6: Installed generating
capacity (MW)
Installed
Level Capacity (M 3 )
1 M 3 > 8,000
2 4,000 < M 3 ≤ 8,000
3 2,000 < M 3 ≤ 4,000
4 1,000 < M 3 ≤ 2,000
5 500 < M 3 ≤ 1,000
6 250 < M 3 ≤ 500
7 0 < M 3 ≤ 250
8 M 3 = 0
Table 4: Total population served
for water supply (number of people)
Total
Level Population Served (M 1 )
1 M 1 > 4,000,000
2 2,000,000 < M 1 ≤ 4,000,000
3 1,000,000 < M 1 ≤ 2,000,000
4 500,000 < M 1 ≤ 1,000,000
5 250,000 < M 1 ≤ 500,000
6 125,000 < M 1 ≤ 250,000
7 0 < M 1 ≤ 125,000
8 M 1 = 0
Table 5a: Annual water
deliveries (millions of dollars)
Annual Water
Level Deliveries (M 2 )
1 M 2 > 800
2 400 < M 2 ≤ 800
3 200 < M 2 ≤ 400
4 100 < M 2 ≤ 200
5 50 < M 2 ≤ 100
6 25 < M 2 ≤ 50
7 0 < M 2 ≤ 25
8 M 2 = 0
Table 7: Annual flood damages
prevented (millions of dollars)
Flood Damages
Level Prevented (M 4 )
1 M 4 > 800
2 400 < M 4 ≤ 800
3 200 < M 4 ≤ 400
4 100 < M 4 ≤ 200
5 50 < M 4 ≤ 100
6 25 < M 4 ≤ 50
7 0 < M 4 ≤ 25
8 M 4 = 0
Consequence-Based Top Screen Process 14