City-Initiated Revisions
Based on comments received from the Santa Clara Valley Water District (Valley Water) on January 5, 2022, the City has initiated the following minor text revisions to Section 4.10, Hydrology and Water Quality, of the Draft IS (deleted text shown in strike-through; inserted text shown in underline). The text revisions below clarify, expand, or update the information presented in the IS/proposed MND. The revised text does not provide new information that would result in any new significant impact or any substantial increase in the severity of an impact identified in the IS/proposed MND, and, therefore, recirculation of the IS/proposed MND is not required.
Section 4.10, Hydrology and Water Quality
The text and associated footnote on page 55 of the Initial Study was revised as follows:
4.10.1.2 Groundwater
The site is underlain by the Santa Clara Plain, Confined, subbasin. In spring 2019, groundwater in the area was recorded at an elevation of about 90.7 feet above sea level. Per Santa Clara Valley Water District (Valley Water) records, the first depth to groundwater is approximately 0 to 10 feet below ground surface at the project site.1
1 Santa Clara Valley Water District. Annual Groundwater Report for Calendar Year 2019 . https://www.valleywater.org/sites/default/files/2020-09/2019_Annual_Groundwater_Report_Web_Version.pdf. Accessed May 7, 2021. Jourdan Alvarado, Valley Water, personal communication, email dated January 5, 2022.
The text on page 55 of the Initial Study was revised as follows:
4.10.1.4 Drainage and Flooding
The project site is located in the Guadalupe River watershed. According to the Federal Management Agency (FEMA), the project site is located in Zone X, which is an area outside the
0.2 percent floodplain and also within an area of reduced flood risk due to levee protection from the one percent (100-year) flood.2
The text on page 57 of the Initial Study was revised as follows:
4.10.3 Hydrology and Water Quality Impacts
Installation of the proposed LED digital billboard would not measurably increase stormwater runoff from the 630 Laurelwood Road project site. Construction of the billboard's foundation structure would result in a small footprint in an already paved area t hat would not substantially impact the amount of runoff from the site or substantially increase impervious surfaces compared to existing conditions. The project site is flat, and, therefore, the potential for erosion on the site is low. The project's earth disturbing activities would consist of drilling a hole (5 feet in diameter and approximately 57 feet deep) for the foundation of the proposed billboard , which could encounter shallow groundwater at the site. If shallow groundwater is encountered during construction, dewatering may be required. To the extent that dewatering activities would be required, water would be stored in tanks, tested, and hauled off -site to avoid and minimize any potential impacts to water quality in the project vicinity. For these reasons, the proposed project would not create additional runoff, diminish water quality as a result of erosion, or otherwise substantially degrade water quality. The proposed project would not result in a significant increase in impervious surfaces and does not require a water supply. Therefore, the proposed project would not decrease groundwater supplies or significantly interfere with groundwater recharge. As a result, the proposed project would not conflict with or obstruct the implementation of a water quality control plan or sustainable groundwater management plan. The project is located within the Lexington Reservoir and Anderson Lake dam failure inundation hazard zones; however, due to existing protections in place dam failure is unlikely and it is not probable that the project would be impacted by dam failure. The project involves a five -foot diameter foundation and its small footprint would not impede or redirect flood flows. The project would not require the use of groundwater or interfere with groundwater recharge, and would not conflict with or obstruct the implementation of a water quality control plan or sustainable groundwater management plan. The project site is not subject to inundation by seiche, tsunami, or mudflow. (Less Than Significant Impact)