Developers building in unincorporated Collin County could soon need a flood study for any project larger than 5 acres or 50 lots, whether or not federal maps show a flood zone nearby. That requirement is part of a rewrite of three sets of county development rules that commissioners may adopt this afternoon.
Commissioners convene in McKinney at 1:30 this afternoon, and their agenda includes the second public hearing on revised Subdivision Regulations, Floodplain Management Regulations and Manufactured Home Rental Community Regulations, which county engineering staff drafted with the consulting firm Kimley-Horn and the county attorney.
The hearing opened Aug. 3 and was left open, and staff met with stakeholders Sept. 3 to go over proposed answers to the comments. Staff recommends hearing more public testimony and then considering adoption.
A comment-response table attached to the agenda shows where builders pushed back and how staff answered.
Flood studies
The Dallas Builders Association opposed requiring a flood study on every development over 5 acres or 50 lots, whichever is smaller, regardless of whether a mapped federal flood hazard area is close by.
Staff recommends keeping it, writing that FEMA maps do not catch every flood-prone creek or drainage area and that large projects can change runoff and flood levels even where no hazard area is mapped. Staff said the rule should be described as a higher county standard, not a FEMA requirement.
The association also asked for exceptions to a rule requiring developers to replace floodplain storage they fill in, when environmental or right-of-way limits make that hard. Staff declined, saying such projects should be redesigned or go through the variance process instead.
