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Yosemite Valley Sanitary Sewer Capital Improvements
Yosemite National Park » Yosemite Valley Sanitary Sewer Capital Improvements » Document List
The Sanitary Sewer Capital Improvement project generally repairs or replaces sewer lines in their existing location and the work is covered by the East Yosemite Valley Utilities Improvement Plan Environmental Assessment. However, there are seven locations where the existing sewer cannot be repaired in place. Pipe needs to be relocated to avoid trees and buildings that are on the line and for improved functionality. These locations include the following which are also shown on the attached construction drawings:
1. Near Residence 21 where the existing sewer runs beneath an alder tree (C-1, photo 001). The work will involve constructing a sewer line and manhole that avoids the tree then abandoning the existing line beneath the tree.
2. Near Residence 18 where the line intercepts the main branch line at the wrong angle (C-1, photo 002). The work will involve construction a new line that intercepts the main branch line at the correct angle.
3. North of the elementary school where the existing line runs beneath two corners of the school building (C-2, photos 003a & b). The work will involve constructing a new line from Building 638 to Residence 62 with a manhole in the alley north and east of the school.
4. On Oak Lane from Residence 9 south the existing line runs through lawns and an oak woodland (C-2 & C-3, photo 004). The work will involve constructing a new line with manholes running down the center of Oak Lane then abandoning the existing line. This relocation is in keeping with the goal of the Utilities Master Plan which called for the relocation of utilities from sensitive resource areas to roads, parking lots, etc. The southern portion of this relocation is covered in the EA for the Utilities Plan.
5. At Ansel Adams Gallery, Building 9031, the existing line runs beneath a large oak tree and takes a needless jog (C-6, photo 005). The work will involve constructing a new sewer line running directly south thereby avoiding the oak as well as creating a more direct routing.
6. In the Lower Pines Campground the main sewer trunk line is going to be replaced because it is asbestos cement pipe (considered hazardous to repair), it is laid with a shallow grade and it is too close to the water main. The pipe will be replaced in its existing location except at the very northern end where it turns east to cross the Merced River (C-14, photos 006a & b). The work will involve constructing the new line with direct routing from MH P3 to MH P1 and abandoning the existing line.
7. In the Lower Pines Campground where the sewer line is too close to the adjacent water line near MH P4. (C-14 & C-15, photo 007). The sewer line and manhole will be replaced to the east maintaining the required 10 foot separation from the water line.
All the new lines are shown in bold lines on the attached drawings. The drawings also show other lines that are being replaced but in the same location as the existing. The typical trench for the relocated lines will be 2 feet wide and the depths will vary with the grade of the pipe, with a minimum depth of 4 feet.
1. Near Residence 21 where the existing sewer runs beneath an alder tree (C-1, photo 001). The work will involve constructing a sewer line and manhole that avoids the tree then abandoning the existing line beneath the tree.
2. Near Residence 18 where the line intercepts the main branch line at the wrong angle (C-1, photo 002). The work will involve construction a new line that intercepts the main branch line at the correct angle.
3. North of the elementary school where the existing line runs beneath two corners of the school building (C-2, photos 003a & b). The work will involve constructing a new line from Building 638 to Residence 62 with a manhole in the alley north and east of the school.
4. On Oak Lane from Residence 9 south the existing line runs through lawns and an oak woodland (C-2 & C-3, photo 004). The work will involve constructing a new line with manholes running down the center of Oak Lane then abandoning the existing line. This relocation is in keeping with the goal of the Utilities Master Plan which called for the relocation of utilities from sensitive resource areas to roads, parking lots, etc. The southern portion of this relocation is covered in the EA for the Utilities Plan.
5. At Ansel Adams Gallery, Building 9031, the existing line runs beneath a large oak tree and takes a needless jog (C-6, photo 005). The work will involve constructing a new sewer line running directly south thereby avoiding the oak as well as creating a more direct routing.
6. In the Lower Pines Campground the main sewer trunk line is going to be replaced because it is asbestos cement pipe (considered hazardous to repair), it is laid with a shallow grade and it is too close to the water main. The pipe will be replaced in its existing location except at the very northern end where it turns east to cross the Merced River (C-14, photos 006a & b). The work will involve constructing the new line with direct routing from MH P3 to MH P1 and abandoning the existing line.
7. In the Lower Pines Campground where the sewer line is too close to the adjacent water line near MH P4. (C-14 & C-15, photo 007). The sewer line and manhole will be replaced to the east maintaining the required 10 foot separation from the water line.
All the new lines are shown in bold lines on the attached drawings. The drawings also show other lines that are being replaced but in the same location as the existing. The typical trench for the relocated lines will be 2 feet wide and the depths will vary with the grade of the pipe, with a minimum depth of 4 feet.