Table 2: Details of two main smaller project excavations Project Dalvatn Slettedalselva Contractor Veidekke ASA Kruse Smith A/S Headrace tunnel length inc. pipe trench (m) 1300 (new) 3660 – section (m2) 14.5-25 (depending on alternative) 18.5 Tailrace tunnel length (m) 280 490 – section (m2) 25 18.5 Access tunnels length (m) 310 + 350 615 – section (m2) 30 + 22 31 Transfer tunnels length (m) 1150 + 2910 + 16,270 0 – sections (m2) 22 + 10 +9.6 0 Intake shaft length (m) 880 0 Power station cavern volume (m3) 13,500 6000 Surge shaft length (m) 190 280 – section (m2) 4-52 6.5