cbg
CIVIL ENGINEERS • SURVEYORS • PLANNERS
October 5, 2021
Job No.: 2065-000
MEMORANDUM
TO: City of Hercules
FROM: Lee J. Rosenblatt, P.E., Principal
CC: Cory Kusich - Santa Clara Housing Group
SUBJECT: Construction Complexity
Hilltown
Hercules, California
Santa Clara Housing Group is preparing the Mello-Roos estimates of cost for the Hilltown project within the City of Hercules. As we all know, every project has its own unique and specific challenges and opportunities. Hilltown, as the name suggests, is on the steep terrain adjacent to San Pablo Avenue in the City of Hercules. The property ranges from elevation 20 to 160 with many steep slopes. The cost to construct a project with this density on hillside far exceeds that on a flat site.
First, this site once contained oil tanks which needed to be removed and the ground beneath remediated. Then, in order to develop, significant corrective grading is required to stabilize the hillsides and make them suitable for construction. This process includes the use of keyways, geogrid, and other geotechnical techniques. However, the most expensive component of the development is the off-haul of excess soil. In order to achieve the required density on the site, the hill is required to be made flatter, by the use of steps, to accommodate the units. While a goal was always to raise the site to keep the soil on site, due to the existing grades on San Pablo Avenue, there were limits on how high this site can be. The total of these costs is significant compared to a flat site.
Additionally, this site has specific constraints that other sites do not. This site does not have an active sewer main adjacent to it. Therefore, a 1,200 foot off-site sewer extension is required for the project to connect to the City system. Furthermore, the site currently has active oil lines, EBMUD transmission mains and PGE transmission lines running through the site. In order to develop the project, all of these facilities need to be relocated outside of the development area. 2633 CAMINO RAMON, SUITE 350 - SAN RAMON, CALIFORNIA 94583 - (925) 866-0322 - www.cbandg.com/
SAN RAMON - ROSEVILLE
P: 2000 - 2099\2065-000 Memos|Memo-003 Construction Complexity.docx cbg
Hilltown Construction Complexity October 5, 2021
As you can imagine, since the lines must remain active during construction, a less efficient grading operation is required to keep the existing lines active while the new alignment and facilities are constructed before the switchover.
Please feel free to contact me if you have any further questions about the complexity of this project.
P: 2000 - 2099\2065-000 Memos|Memo-003 Construction Complexity.docx