Page - 1063 - in Book of Full Papers - Symposium Hydro Engineering

threaten the integrity of the dam. Figure 4 shows the eroded area downstream the left spillway chute. Figure 4 Eroded area (marked red) downstream of the left chute at Ramsele (Norconsult, 2014). 2.3. REHABILITATION OPTIONS In order to fulfill the design requirements cost-effectively, a number of rehabilitation options were studied in separate feasibility studies for both dam facilities. 2.3.1. Långströmmen The following alternatives were evaluated, with the objective to increase the total discharge capacity (Ygland et al, 2012): 1. Modifications of the existing timber spillway by lowering its threshold 2. A new spillway to the right of embankment 5 3. A new spillway between embankments 4 and 5 4. A new spillway in combination with a siphon spillway 5. An emergency spillway with an erodible dam section 6. An emergency spillway with an automatically regulated flap gate 1063