CONSTRUCTION DISRUPTION
Construction is an all too familiar sight for residents of Los Angeles. As a result, natives must deal with constant loud noises, difficulties finding parking and even more traffic than usual. However, in addition to these ailments, development projects in West Hollywood may be causing environmental issues.
Building developers in West Hollywood have been creating large-scale apartments to accommodate more residents. In order to comply with the area’s zoning laws and building height restrictions, they are going underground and digging out full basements to give them more square-footage. However, because of the area’s high water table, these building sites are forced to continuously pump out groundwater during construction, and often for a time afterwards, to avoid flooding. The water is pumped directly into street sewer drains, where it travels to Ballona Creek and eventually Santa Monica Bay.
This process, known as dewatering, has led to several concerns among residents in West Hollywood. Specifically, dewatering may be having an adverse effect on the local vegetation as well as the water quality of Ballona Creek and Santa Monica Bay. Residents have reported six trees deaths along Westbourne Drive within the last year. Two of the six were drought tolerant Acacia trees. Originally worrying the tree was diseased, Jay Jacobsen brought in an arborist who concluded that the tree was dying from a “lowered water table”.
SIX TREE DEATHS AND COUNTING
For properties with underground construction, developers are required by the city’s Building and Safety Division to have a geotechnical engineer assess any potential impact to surrounding areas. According to a report from the West Hollywood Community Development Department (CDD), “dewatering can artificially lower the water table in adjacent areas and could lead to groundwater settlement of nearby private and public properties.”
However, the CDD believes that West Hollywood is not vulnerable to groundwater displacement from underground construction. In their report, they state, “the city’s current process ensures that precautions are taken throughout the development review process to prevent and/or mitigate any environmental impacts within the surrounding area.”
A 2004 study by the departments of geography and environmental studies at UC Santa Barbara examined the environmental impacts of long-term groundwater extraction in the southwestern United States. When extraction exceeds the amount of water recharge by rain and surrounding resources, it can lead to overdraft, which may result in ecological issues like land subsidence and seawater intrusion. In addition, they stated that, “long-term decline of the water table can be acutely detrimental to vegetation.”
While the study examined the results of large-scale groundwater pumping, the effects of local construction projects may be affecting the vegetation in West Hollywood. Residents have reported six trees deaths along Westbourne Drive within the last year.
When the Sierra Club’s Los Angeles Chapter Water Committee reached out to the Wildlands Conservancy for information, their certified arborist stated via email that, “by pumping out groundwater (especially if it is in a high water table) you will be adversely affecting the tree’s health if they have developed tap-roots which tie into the water table, and would be a major source for the tree if so.”
The deceased trees are located near two active dewatering sites, 546 Westbourne Drive and Restoration Hardware. Upon applying for the general National Pollutant Discharge Elimination System (NPDES) permit required for dewatering, a fact sheet provided by the contractors at 546 Westbourne Drive stated, “up to 1,000 gallons per day of groundwater will be discharged into the storm drain located along Westbourne Drive… the discharge from the storm drain flows into Ballona Creek.” The construction project is estimated to last six months, potentially totaling 180,000 gallons of water.
Dewatering is the largest portion of electricity consumption (74 submersive pumps needed for 180 days for one “unit procedure”) = 194,400 kwh/unit procedure (all other categories totaled = 22,969 kwh).
TOXIC GROUNDWATER
Water that is pumped from construction sites is being deposited directly into sewer drains. These drains bring the water to Ballona Creek and eventually Santa Monica Bay, without any filtration provided by the city or the state.
According to the report by the CDD, this water is considered too contaminated to even be “non-potable”, a reclaimed water resource often used for toilets or lawns. In their report, they state, “West Hollywood’s soil and groundwater supply has suffered from historic contamination as a former oil field and interurban railroad destination. This contamination impedes on the ability for the City to reuse its surface groundwater for irrigation or other uses suitable for non-potable water sources without extensive treatment and purification.”
Therefore, to monitor potential contaminants being pumped into the Creek, projects requiring permanent or temporary dewatering, where the discharge of groundwater could affect California’s waters, must first get an NPDES permit. These permits govern and restrict the amount of pollutants that can be discharged into a body of water.
“Throughout the dewatering process, specific requirements regarding water quality testing, filtration and treatment, discharge limitations and prohibitions, and monitoring and reporting must be followed, according to the protocols of the NPDES permit,” the report states.
REUSING GROUNDWATER
In order to recycle groundwater for non-potable uses such as irrigation or toilet flushing, it must be tested and treated to meet the Los Angeles County Department of Health’s (DOH) Guidelines for Alternative Water Sources. Based on the complexities of these standards, the CDD stated an impracticality for applying such a system to all dewatering sites. Instead, they recommend the establishment of a groundwater reuse system only for large properties with permanent dewatering. However, existing sites meeting this description, such as the Pacific Design Center Red Building and the Center for Early Education, after exploring the implementation of a reuse system, have not proceeded with plans due to the difficulties with meeting the water quality standards, among other factors.