The City of Manor Planning and Zoning Commission approved an amended subdivision concept plan and an amended preliminary plat for Holly Smith (also called Mustang Valley), a proposed 399‑lot development on about 136.92 acres at 15200 North FM 973.

The actions come after several residents raised concerns about stormwater, drainage and review time. Krista Sweer, a homeowner on FM 973, told the commission that “we do not have water quality control in the city of Manor,” and urged the city to require developers to retain and reuse stormwater rather than relying on detention ponds that release flows downstream.

The commission approved a related agenda item (item 6) by a 3‑1 vote; Commissioner Meyer cast the lone dissent. Separately, the commission approved the amended preliminary plat (item 7) by a 4‑0 vote.

Why it matters: Nearby residents told commissioners they have observed new, persistent flows through their properties and said they believe additional impervious cover from the development has increased runoff. The applicant and city engineers said the subdivision’s drainage design was prepared to current design standards and reviewed by the city.

What staff and the applicant said: John Zinsmar, vice president of land for KB Home, and Lee Whited, the project civil engineer for Carlson Brigance & Doring, described the project’s drainage design and submitted as‑built drawings and revised drainage studies after earlier construction. Whited said the project was designed to Atlas 14 rainfall values and that detention features were sized to attenuate post‑development peak flows back to pre‑development rates.

Pauline Grama, the city engineer, told commissioners the plans show the FEMA 100‑year floodplain where required and that staff reviewed the drainage calculations and plans for ordinance conformance. She confirmed that the floodplain mapping shown to the commission reflects the FEMA mapping currently used in the city’s review and that Atlas 14 design rainfall was used for the engineering calculations.

Public concerns and staff response: Property owner Krista Sweer told the commission she received plans too late to consult engineers and attorneys, that the applicant’s plans show a stream across part of her property that she said does not appear on her recorded plat, and that KB Home’s work on earlier phases increased surface flows onto her land. Whited and Grama said the FEMA floodplain crosses the area, and that detention ponds upstream are designed to control peak flows rather than retain long‑term flows; detention ponds “catch and release” rather than serve as retention. Staff emphasized that plans must demonstrate no increase in off‑site peak flow to gain approval.

Decisions and next steps: The commission closed the public hearing on the concept amendment and moved to consider the regular agenda. Item 6 — the amended concept change — passed 3‑1; item 7 — the amended preliminary plat — passed 4‑0. The approvals allow the applicant to proceed with the revised subdivision documents; subsequent permitting and construction will be subject to engineering review and permit conditions.

What remains open: Residents asked the city to adopt water quality/retention standards beyond detention ponds; those policy decisions were not adopted at the meeting. Several public commenters also asked for more time to review plan revisions before final action; the record shows commissioners debated timing and state review timelines during the discussion.

Ending note: Commissioners and staff said future plan submittals and site work remain subject to engineering review and permits, and the approved amended plat will move forward to the next administrative permitting steps.