The Highland Park Community Development Association asked the Des Moines City Planning and Zoning Commission on Oct. 2 to recommend rezoning 3851 Sherman Boulevard so the group can renovate an existing house and build a duplex and two accessory dwelling units, for a total of five residential units.

Planning staff recommended conditional approval, saying the applicant revised an earlier plan that proposed seven units and had created too much impervious area. ‘‘With the updated proposal, staff does think that this proposal is appropriate in this area,’’ Sriyoshi Chakraborty, planning staff, told the commission.

The rezoning request would change the parcel’s zoning from N3A (neighborhood district) to NX1 (neighborhood mixed), allowing the mix of dwelling types proposed. Under the applicant’s revised plan the parcel, about 0.9 acres, would retain the existing single-family house, add a duplex fronting Sherman Boulevard, and include two accessory dwelling units behind the principal structures. Staff outlined conditions for approval, including limiting the lot to a maximum of five dwelling units, requiring substantial compliance with the submitted development concept to the satisfaction of the planning and urban design administrator, stormwater management to the satisfaction of the city engineer, and vehicular access limited to a single driveway with any unused drives removed and restored.

The plan originally submitted proposed seven units and prompted a staff recommendation of denial because staff said the earlier layout maximized coverage, increased impervious surfaces and lacked adequate open space and setbacks. The applicant revised the plan, replacing a wider cul-de-sac with a narrower private drive and reducing the unit count to five; staff said that change addressed earlier concerns.

Neighbors who spoke at the public hearing urged denial or careful review. ‘‘This development and keep in mind, we’re in Beaverdale ... You don’t put a commercial venture back in the back lots,’’ said Michael O’Malley, who lives at 3919 Sherman Boulevard, describing concerns about lot depth, privacy and increased traffic. Fred Walker, a longtime resident, said the proposal would ‘‘seriously impact us in a negative way’’ and raised concerns about density, parking and potential effects on property values.

Several speakers focused on stormwater. ‘‘There is a storm sewer running along Sherman Boulevard ... our recommendation is that the applicant look at a mechanism of controlled discharge directed toward Sherman Boulevard because there is an existing storm sewer,’’ Chakraborty said when summarizing engineering input. Other residents described past flooding and a buried spring on the site and asked how the proposed additional impervious area would be controlled; city staff repeatedly said final stormwater plans would be developed during the site-plan and engineering review phases and must satisfy the city engineer.

Philip Herman, director of community engagement for the Highland Park Community Development Association and the project applicant, said the organization intends to keep the parcel a single lot and to develop permanent supportive affordable rental homes. Herman told the commission the association anticipates using grant funding that would require the units be kept affordable for 18 years after occupancy and described the intended tenant population and supportive services. ‘‘We are proposing ... permanent supportive rental housing. That’s a federal term, and we would fall under those guidelines,’’ Herman said.

Staff also reported neighborhood outreach and two mailings after the applicant revised the plan. Staff presented two ‘‘consent maps’’ showing the relative opposition recorded on comment cards: the first round of notices produced an opposition share the staff reported as about 58.07 percent; the second, updated set showed opposition of about 45.25 percent. Chakraborty reminded the commission that because opposition exceeded 20 percent, a council decision on the rezoning would require a supermajority vote.

After public comment and applicant rebuttal, a commissioner moved to forward the staff recommendation to city council; the motion passed by voice vote. The commission’s recommendation is advisory; final approval of the rezoning request rests with the Des Moines City Council, which will consider the item at a later public hearing and, because of the measured opposition, would require a supermajority vote to adopt the rezoning.

Details for next steps: if the council approves the rezoning and the applicant proceeds to site-plan review, the project will be required to meet the zoning conditions listed in the staff report, have a stormwater management plan approved by the city engineer, and follow the city’s house-type and design standards for the NX1 district.