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Sid Commons FAQs

What is the Sid Commons Project?

The project consists of residential development and terracing of the Petaluma River on an undeveloped property located at the end of Graylawn Avenue. The conceptual site plan has been revised since the project was initially proposed and now consists of 180-units contained within 2 and 3-story buildings.

Does the project site contain wetlands? 

Yes. The approximately 16 net acre project site contains 0.29 acres of wetlands and 0.33 acres of isolated wetlands as verified by the Army Corps of Engineers (see Figure 6-3 in the DEIR). The largest wetland (P3) and the two smaller isolated wetlands (C1 and D1) will be retained. The project would result in fill to the remaining isolated wetlands. As such a Nationwide Permit from the Army Corps of Engineers pursuant to Section 404 of the Clean Water Act would be required prior to any construction activity. Additionally, the Regional Water Quality Control Board also regulates wetlands through the Porter-Cologne Water Quality Act and Section 401 of the Clean Water Act. The project is required to offset fill to wetlands (Mitigation Measures Bio-4) and proposes to introduce approximately 0.47 acres of created wetlands onsite as part of the terrace design.

Is the project proposing development in the floodplain?

No. The project development footprint is located outside of the 100-year floodplain. See Figure 2-2 in the FEIR. 

Why does the project include terracing of the River Bank?

The requirements for flood control are set forth in the General Plan under Goal 8-G-8 beginning on page 8-16. In particular, Policy 8-P-28 calls for the construction of a flood terrace system. It is through this policy that Sid Commons has been required to include the terracing component. The policy was informed by hydrologic modeling that was conducted as part of the General Plan. Project specific hydrologic modeling for the Sid Commons project as well as reach wide modeling was also conducted and is presented in the DEIR. Modeling demonstrates that the greatest benefit to citywide flood control is achieved through a combination of terracing upstream of the weir accompanied by upstream detention.

Does terracing benefit the project?

No. The project does not receive any benefit from terracing. Although terracing at the project site does reduce the boundary of the 100-year floodplain onsite, the project development footprint is already located outside of the 100-year floodplain. Terracing is being imposed by the City as a requirement of development to realize the Citywide flood control objectives.   

Why does the project site hold standing water after a rain event?

As presented in the Final EIR and described in detail in the DEIR a majority of the site is overlain by Yolo and Clear Lake soils, which exhibits low permeability (water does not easily filter through the soil), is poorly drained, and has high rates of runoff. Yolo and Clear Lake soils function in manner where once the soil column is saturated, which doesn't take much for this soil type, water pools and sheet flows following the downward gradient, which at the project site, generally slopes towards the River. Page 4-29 of the FEIR presents the Master Response to Stormwater Runoff comments and specifically addresses stormwater flows, ponding onsite, saturation and runoff. 

Will the project be affected by Sea Level Rise?

No. The project site is located higher up in the watershed and upstream of where the Petaluma River is tidally influenced. Additionally, the project respects and exceeds the 200 foot setback from the Petaluma River, thereby providing a buffer between the River and where new residential development would occur. Sea level rise is addressed on page 11-43 of the DEIR.

Will Trees be removed?

All protected trees on APN-009 including trees within the River Plan Corridor and those identified for preservation by the River Access and Enhancement Plan will be preserved under the 180-unit concept plan. 

Where can I get more information?

The environmental document and attachments are available at the following link:

https://cityofpetaluma.org/sid-commons/

The Staff Report and attachments for the upcoming February 3, 2020 council hearing are available at the following link:

http://petaluma.granicus.com/GeneratedAgendaViewer.php?view_id=3&event_id=44343

Sid concept plan

The Project includes a conceptual site plan for a 180-unit apartment complex, with the apartment units located within separate two- to three-story apartment buildings.

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