Final Notice and Public Explanation of a Proposed Activity in a 100-Year Floodplain
To: All interested Agencies, Groups and Individuals
This is to give notice that the HUD has conducted an evaluation as required by Executive Order 11988, in accordance
with HUD regulations at 24 CFR 55.20 Subpart C Procedures for Making Determinations on Floodplain Management and
Wetlands Protection. The activity is funded under Section 221(d)(4) of the National Housing Act.
The subject property is located on the southwest corner of the intersection of East 9th Street and South Stewart Street within an urbanized, commercial area of Carson City, Nevada. According to Carson City County Property Inquiry database, the subject property parcels are identified by parcel identification numbers 00405502 and 00405507. The subject property is proposed for multi-family development consisting of a five-story apartment building with 253 residential units. The building design has a footprint of approximately 114,000 square feet and partially wraps around a six-story parking structure. The apartment building will include a leasing office, a two-story club house, and additional amenities. The project areas include the proposed HUD-insured (collateral) property and non-collateral right of way improvements, which total an area of approximately 4.11 acres. The collateral property consists of 3.44 acres of vacant unoccupied land with a gravel-covered ground surface and areas of concrete pads from previous structures on the northern portion.
According to the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) Community Panel
Number 3200010092G, dated December 22, 2016, the majority of the subject property appears to be located in Flood Zone X, Shaded, which is an area subject to the 0.2 annual percent chance flood hazard located between the limits of the 100- and 500-year floodplains. The southern and southeastern portions of the subject property are located within Flood Zone AO, which indicates a Special Flood Hazard Area (SFHA) and is an area subject to the 100-year flood in the form of sheet-flow shallow flooding with depths between one and three feet. The base flood elevation (BFE) is established as a depth of one foot. As currently proposed, a total of approximately 0.193 acres of the Zone AO floodplain will be disturbed and developed with the proposed building, a stormwater detention basin, sidewalk, utility, and right-of-way improvements. These actions will involve filling, grading, and incorporating impervious surfaces on the collateral and non-collateral project areas located within the floodplain.
The Carson City Planning Division approved a Special Use Permit (SUP) application for the proposed project on December 15, 2020 with the requirements that Carson City Development Standards are met, including 1.) that the project must obtain a FEMA Letter of Map Amendment (LOMA) approval prior to a site improvement permit being issued and 2.) the private storm drain must tie into the City storm main at a new manhole. As such, the subject property will be filled and graded to construct the proposed building two feet above the BFE. Furthermore, per Carson City development requirements, a Conditional Letter of Map Revision Based on Fill (CLOMR-F) application will be submitted to the Carson City Floodplain Manager and FEMA.
According to a Conceptual Drainage Study by Manhard Consulting Ltd, the proposed detention basin would consolidate the area of the floodplain to be outside of the building footprint and would provide equal flood water storage of existing conditions. Furthermore, the detention facility would detain the required amount of discharge in the 100-year storm event with negligible impact to downstream facilities and surrounding areas. An alternative stormwater mitigation option in lieu of the stormwater detention basin is being considered, which would consist of a subterranean infiltration basin of identical volume to be positioned on the western side of the subject property under the proposed emergency access and outside of the SFHA. If the subterranean infiltration basin method is utilized, the area currently shown on the construction plans as the detention facility would be revised to a pervious landscaped area, reducing the site’s impervious surfaces.
With either stormwater mitigation system option, floodwater storage at the subject property will not be affected. The
anticipated natural and beneficial functions and values of the floodplain that may be adversely affected by the proposed
activity consist of an alteration of floodwater conveyance patterns. Additionally, as the subject property consists of
vacant unoccupied land with unpaved gravel and concrete-covered ground located in an urbanized setting, water quality
maintenance, flora and fauna, agricultural, aquacultural, and forested resources are not anticipated to be impacted by the
proposed development.
HUD has considered the following alternatives and mitigation measures to be taken to minimize adverse impacts and to
restore and preserve natural and beneficial values: With the minimized floodplain impacts and ability to provide mitigation
for the proposed development, the no action alternative is impracticable because it will not satisfy the demonstrated need
to provide singles and families with opportunities for housing within Carson City. The subject site was selected due to the
minimal floodplain hazard onsite as compared to other developable properties in the surrounding areas. In order to comply
with Carson City’s pedestrian access requirements, the southeastern portion of the subject property is required to provide an impervious sidewalk surface. Based on the lack of capability of complete avoidance of the floodplain due to local pedestrian access and right-of-way requirements, the avoidance of floodplain development on the subject property alternative is also impracticable. Although the subject property is in a floodplain, the project has been adapted in order to minimize effects on floodplain values. Steps were taken in order to minimize risks to human life and property via evacuation plans, construction methods, stormwater management design, and flood insurance. For the subject property, the result of flood within the occupied areas, specifically residential units, is not anticipated as the occupied areas will be located at a minimum of two feet above the BFE. The CLOMR-F will remove approximately 0.128 acres of the southern portion of the subject property from Flood Zone AO and will result in the proposed building being entirely located outside of the SFHA.
If the project proceeds with the currently proposed stormwater detention basin mitigation measure, the installation of the
detention basin will incur impacts to the SFHA. However, based on the Conceptual Drainage Study, an equal amount of
floodwater storage would remain at the subject property following development. Stormwater conveyance would be altered in changing the four exisiting drainage basins into seven proposed drainage basins and directing stormwater to the detention facility to later empty into the existing storm drain lateral on the southeastern portion of the subject property. The rate of discharge of stormwater from the detention basin will be equivalent to the existing rate emptying into the existing storm drain main. The option to incorporate a subterranean infiltration basin would allow for increased groundwater discharge/recharge at the subject property, rather than the stormwater being directed to the municipal stormwater system. As a result, this option is not expected to have a significant impact on stormwater conveyance.
HUD has reevaluated the alternatives to building in the floodplain and has determined that it has no practicable alternative.
Environmental files that document compliance with steps 3 through 6 of Executive Order 11988 are available for public
inspection, review and copying upon request at the times and location delineated in the last paragraph of this notice for
receipt of comments.
There are three primary purposes for this notice. First, people who may be affected by activities in floodplains and those
who have an interest in the protection of the natural environment should be given an opportunity to express their concerns
and provide information about these areas. Commenters are encouraged to offer alternative sites outside of the floodplain,
alternative methods to serve the same project purpose, and methods to minimize and mitigate impacts. Second, an adequate public notice program can be an important public educational tool. The dissemination of information and request for public comment about floodplains can facilitate and enhance Federal efforts to reduce the risks and impacts associated with the occupancy and modification of these special areas. Third, as a matter of fairness, when the Federal government determines it will participate in actions taking place in floodplains, it must inform those who may be put at greater or continued risk. Written comments must be received by HUD at the following address no later than 7 days from the date of this notice. A full description of the project may also be reviewed upon request. Comments should be addressed to Shaun Fontenelle, Multifamily Review Construction Analyst, U.S. Department of HUD, 1670 Broadway, Denver CO 80202. Envelopes without a complete return address will not be opened. Additionally, all contact information must appear on the letter itself. Comments may also be submitted via email at: Shaun.P.Fontenelle@hud.gov.
Date: June 11, 2022
Pub Date: June 11, 2022 Ad # 24912