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Conditional Approval for Arcadia rEWMP Project Area

Figure of site layout for Arcadia Arboretum Natural Treatment and Groundwater Recharge Project. – Courtesy photo / Water Board Calif.

By Susan Motander

The reaction to that headline should have been a resounding “What?”.  This is an important issue as it may affect your taxes and water rates.

But first, you will need a few explanations and definitions. An Enhanced Watershed Management Plan is an EWMP (pronounced E-Wimp – appropriately).  An rEWMP is a revised EWMP (pronounced: Are-E-Wimp).  All of this “bureaucrat-speak” is the result of the Regional Water Board demanding more stringent cleaning of our local storm water (which you will note in “bureaucrat-speak” is now one word) than any other water board in the state and as far as we know the nation.

The first numbers for the projects required by the Water Board were staggering; they were in the billions for the county and the millions for each local community. The amount required for some cities could equal a decade of their entire local budget for the entire city. Potentially, if this went through, cleaning the storm water would be the only thing a city could fund and it could bankrupt them (and we all thought funding the employee retirements was a problem).

The original EWMP for this area was around $1.4 billion to clean up storm water to achieve compliance with the mandated MS4 Permits (no this is not the dangerous drug gang, but rather a Municipal Separate Storm Sewer System). Are we all following along?

We have revised our original EWMP and the cost for the region has dropped to $122 million. As Monrovia City Manager Oliver Chi claims, this is a 91 percent savings over the original estimate for the area. The region includes the cities of Monrovia, Arcadia, Duarte, Bradbury, Sierra Madre, Azusa, as well as the LA County Flood Control District for the area. The cost of the four proposed projects in the area will be shared by all the entities in the regional plan.

In his City Manager’s Update last week, Chi noted that with the passage of Measure W in November of 2018 there will be approximately $32.1 million per year to spend on storm water capital improvements in two different watershed areas involved in our rEWMP: Rio Hondo and Upper San Gabriel River. Prepare yourself: There are more sets if definitions coming.

Recently LA County coordinated the selection process for filling the municipal seats on the Watershed Area Steering Committees (WASCs). Monrovia for example was selected as the primary municipal representative on the Rio Hondo WASC and as the alternate for the Upper San Gabriel River WASC (dare we call this the Usger Wasc). At the City Council Meeting on Jan. 15, Gloria Crudington was selected to represent Monrovia on both these WASCs with the City Manager as her personal alternate.

There are four main projects in the rEWMP: one each principally in Arcadia, Monrovia, Duarte and in the Santa Fe Spreading Grounds.

The project in Arcadia would divert water from the Arcadia Wash, treat it and ultimately release the water into Baldwin Lake (AKA the Lagoon). The project that will take place largely in Monrovia also diverts water from the Arcadia wash and will take place in two phases.  The first would divert water from the Wash to recharge the San Gabriel Groundwater Basin by sending it to Sawpit through treatment down to the Peck Road Flood Control and Water Conservation Basins.  The second phase would take the water from the Arcadia and Sawpit Washes and attempt to turn the various settling basins and treatment area into a restored wetland ecosystem.

Then we move further east to the Duarte project mainly under Encanto Park. This would take water from the LA County Flood Control District Storm Drain into a pretreatment devise and then into storage and settlement chambers, storage vaults and infiltration areas. The last project is the one at the Santa Fe Spreading Grounds. This would take water from the Bradbury Channel, send it through a sediment basin, then around baffle walls and ultimately this treated water would go to the San Gabriel River.

But there are challenges with each project.

The Arcadia Arboretum Natural Treatment and Groundwater Recharge Project, as the venture at the Arboretum is formally called, starts with a diversion to move water from the Arcadia wash through a trash rack (to catch the big stuff) into a sediment forebay to allow the smaller sediment to settle. From there the water will flow through two groundwater recharging ponds to allow the some of the water to percolate back to the water basin. Between the two GW Recharge Ponds there will be a wetlands pond. There is also a proposed dry weather pump station at the wash to keep the system active in dry weather. From the wetlands pond the water will be pumped via a natural creek to Baldwin Lake.

This whole project including removing some of the existing large pipes that remove water from the lake and return it to the wash is estimated to cost $5,893,433.  The tule pond that now exists between the lake and the wash will be restored as a planting area.  This is a joint project between the cities of Arcadia and Sierra Madre and the County Flood Control District.

There are some concerns about this project. A lot of excavation will be required. The best way to keep the system working and to keep cost low is to ensure that it is gravity fed. There will be a rubber dam at the wash at the head of the project to divert water from the wash into the system. There will also be various gates installed to regulate the flow of water. There is concern that without enough water moving through the system, it might be hard to keep the wetlands wet and continuing to restore Lake Baldwin.

The next project moving eastward is the Arcadia Wash Conservation Diversion, a joint project between Arcadia, Sierra Madre, Monrovia and the County.

February 20, 2019

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Susan Motander


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