The purpose of this section is to establish minimum stormwater management requirements and controls to protect and safeguard the general health, safety, and welfare of the public within this jurisdiction. This section seeks to meet that purpose through the following objectives.
(1) 
Manage and control stormwater runoff in a safe and economical manner in developing areas for the purpose of promoting the health, safety and general welfare of the population, and for the protection of property.
(2) 
Protect the citizens of Cedar Park by preventing dangers arising from improper drainage facilities, inadequate construction of drainage facilities and unwise diversion, use and obstruction of waterways and planning for the present and future use of waterways through the establishment of regulations governing development on and adjacent to the waterways.
(3) 
Limit the alteration of the native waterways to prevent unnecessary destruction of the natural beauty, character and economic value their existence provides to the city.
(4) 
Minimize the total annual volume of surface water runoff which flows from any specific site during and following development to not exceed the predevelopment hydrologic regime to the maximum extent practicable.
(5) 
Provide for stormwater storage within the city where detention/retention basin facilities have been determined to be beneficial in reducing the peak runoff to subservient lands.
(6) 
Reduce stormwater runoff rates and volumes through stormwater management controls and ensure that these management controls are properly maintained and pose no threat to public safety.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
The provisions of this section shall apply to all major subdivision, development plat and/or site development activities requiring land use permits and approvals within the City limits and the extraterritorial jurisdiction of the City, unless otherwise excluded within this section. The section also applies to land development activities that are smaller than the maximum square footage exempted if such activities are part of a larger common plan of development. In addition, all plans must also be reviewed by either TCEQ (if located within the Edwards Aquifer contributing and/or recharge zones) or the City on behalf of LCRA (if located within the Lake Travis Watershed) to ensure that established water quality standards will be maintained during and after development of the site. TCEQ approval is required prior to site development permit issuance.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
(a) 
The following situations are exempt from the requirements of this section:
(1) 
Agricultural use of land;
(2) 
Additions or modifications to existing single-family structures;
(3) 
Development or redevelopment projects whereby no more than one thousand (1,000) square feet of additional or new impervious cover is created, provided they are not part of a larger common development plan;
(4) 
Emergencies posing an immediate danger to life or property, or substantial flood or fire hazards.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
The Director of Engineering or his/her designated representatives may enter upon any property which discharges or contributes, or is believed to discharge or contribute, to stormwater runoff or the stormwater system, stream, natural drainageway, or other stormwater system during all reasonable hours to monitor, remove foreign objects or blockages, and to inspect for compliance with the provisions of the chapter.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
There is hereby adopted by the City of Cedar Park for the purpose of establishing rules and regulations for the design, development, construction, alteration, enlargement, repair, conversion, equipment, use, height, area and maintenance of drainage improvements, that certain codes recommended by the City of Austin Drainage Criteria Manual, being the most current edition thereof, and the whole thereof, as amended from time to time, including later editions, except such portions as are hereinafter amended, deleted or modified by the City of Cedar Park. One (1) copy of said code is now on file in the office of the City Secretary, and the same is hereby adopted and incorporated as fully as if set out at length herein, and the same shall be controlling in the design, development, and construction of all drainage improvements within the city limits and extraterritorial jurisdiction of the City of Cedar Park, Texas.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
Except as authorized by an approved site plan, no person shall place or cause placement of any obstruction of any kind in any waterway within the city. The owner, agent, lessor, or other person in control of any property within the city, through which any waterway may pass, shall keep the waterway free from any obstruction not authorized by a site plan; and any pool of standing water which is formed in any waterway within the city on account of any unauthorized obstruction shall be deemed and same is hereby defined to be a nuisance.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
(a) 
No preliminary plan, final plat, development plat, subdivision construction plan, or site plan shall be approved unless:
(1) 
The proposed preliminary plan, final plat, development plat, subdivision construction plan, or site plan provides a sufficient waterway for the design flood, determined in accordance with the drainage criteria manual;
(2) 
Any proposed improvements are of sufficient strength to resist any pressure of earth or building from the outside and pressure or abrasion of water and debris from the inside;
(3) 
All proposed grades are such that water will not gather in pools which may become stagnant or foul;
(4) 
The proposed development will not result in additional identifiable adverse flooding of other property; and
(5) 
Both temporary and permanent erosion control measures are adequate to minimize siltration of the waterway as approved by the Engineering Department.
(b) 
It shall be the responsibility of the developer to design and construct a system for the collection and transport of all stormwater runoff flowing into, and generated within the development, in accordance with:
(1) 
The requirements of this article;
(2) 
The City of Austin Drainage Criteria Manual, as currently amended, save and except as noted in this article;
(3) 
Good engineering practices;
(4) 
Approved engineering plans for construction;
(5) 
The regulations and principles of law established pursuant to the Texas Water Code; and
(6) 
The best available data from local, state and federal agencies or sources.
(c) 
The fiscal security required under Chapter 12 shall be made sufficient to cover the cost of:
(1) 
Installing and maintaining erosion and sedimentation controls throughout construction;
(2) 
Revegetation;
(3) 
On and off-site cleanup; and
(4) 
Remedying any erosion damage resulting from development pursuant to this permit.
(d) 
The fiscal security shall insure the installation, maintenance, performance, and/or remedy of the following, without cost to the City, in the event the applicant fails to:
(1) 
Install or maintain adequate erosion and sedimentation controls; revegetate;
(2) 
Perform on and off-site cleanup; and
(3) 
Remedy erosion damage.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
(a) 
In addition to the requirements of section 12.16.007, no site plan for property within the zoning jurisdiction of the city shall be approved if a proposed building shown on the site plan encroaches in the one-hundred-year floodplain, as the same is calculated to exist under fully developed undetained conditions, in accordance with the drainage criteria manual.
(b) 
Subsection (a) shall not apply to construction of a parking area of less than 5,000 square feet or an unoccupied structure of less than 1,000 square feet where the Engineering Department has determined the proposed development does not have an adverse effect on the floodplain or surrounding properties and is otherwise in compliance with the requirements of this chapter.
(c) 
The engineering director or his/her designee shall have the discretion to approve a site plan for construction, notwithstanding noncompliance with the conditions set forth in this section, when the applicant submits a written request specifying the conditions requested to be waived, accompanied by a detailed justification signed and sealed by a Texas registered professional engineer certifying that the request will not result in additional adverse flooding of other property, and the engineering director or his/her designee determines that the request constitutes a minimum departure from the conditions set forth in this section, that such departure is necessitated by the unique conditions of the site, and that such departure does not create an adverse flooding condition for other properties.
(d) 
No proposed parking area shall encroach upon the one-hundred-year floodplain, as the same is calculated to exist under fully developed undetained conditions in accordance with the drainage criteria manual unless:
(1) 
The level of water detention or waterflow in such parking area during the 100-year storm exceeds neither an average depth of eight inches (8") nor a maximum depth at any point of twelve (12) inches; and
(2) 
Appropriate notice signs, as approved by the Engineering Department are posted if any water detention or water flow in such parking area may exceed a depth of eight (8) inches at any point.
(3) 
No building or parking lot construction shall encroach upon the twenty-five-year floodplain, as the same is calculated to exist under fully developed undetained conditions in accordance with the drainage criteria manual.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
(a) 
The owner of property to be developed may be required by the Engineering Department to provide, at the owner’s expense and as a condition for preliminary plan, final plat, development plat, subdivision construction plan or site plan approval, a drainage study for the total area to be ultimately developed. The study shall be in accordance with the drainage criteria manual, and shall be submitted to the department for approval prior to the acceptance for review of any construction plans for any portion of the development.
(b) 
If any portion of a proposed development is included within a floodplain or floodway delineation accepted or recognized by the city, such delineation shall be clearly shown on all preliminary plans, final plats, development plats, subdivision construction plans, and site plans submitted for approval.
(c) 
The Engineering Department shall designate and maintain official floodplain maps. In any case in which official floodplain maps are not available, the owner of property to be developed shall designate the boundaries of the one-hundred-year floodplain in accordance with the drainage criteria manual and shall clearly show such on all preliminary plans, final plats, development plats, subdivision construction plans, and site plans submitted for approval.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
On any lot designated on a plat or subdivision construction plan as requiring completion or partial completion of drainage improvements prior to any building construction, no building permit or certificate of compliance shall be issued for the lot until the Engineering Department has approved the issuance of the permit or certificate.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
(a) 
Computation of stormwater runoff shall be based on a fully developed undetained contributing drainage area or watershed and shall be in accordance with the drainage criteria manual.
(b) 
Easements or rights-of-way shall be dedicated by the owner of the property to be developed to the public for the purpose of containing all drainage facilities, open or enclosed, and all stormwater flows to the limits of the one-hundred-year floodplain as determined in accordance with subsection (a). No easement or right-of-way for such purposes shall be less than twenty-five (25) feet in width for open drainage systems or fifteen (15) feet for enclosed drainage systems. Additional easements or right-of-way shall be provided as necessary to allow continuous access for operation, maintenance, and rehabilitation of all drainage facilities. Any part of a lot or tract of land contained within such easement or right-of-way may be counted as part of the area of the lot or tract of land for the purposes of density and impervious cover calculations.
(c) 
Within any street right-of-way, an enclosed storm sewer system shall be required to accommodate that portion of the design flow which exceeds street capacities in accordance with the drainage criteria manual.
(d) 
The design and construction of all drainage facilities and improvements shall be in accordance with the drainage criteria manual and shall include provisions for maintenance and protection from erosion.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
Whenever any creek, drainageway, or watercourse is covered, manholes not less than two (2) feet in diameter, with removable covers, shall be installed in accordance with the drainage criteria manual. All such work shall be done under the supervision of the Engineering Department and shall be subject to inspection at any time by officers and employees of the city.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
(a) 
The owner or developer of property to be developed shall be responsible for the conveyance of all stormwater flowing through the property. This responsibility includes the stormwater directed to the property by any developed property as well as the drainage naturally flowing through the property by reason of topography. Future upstream development shall be accounted for in accordance with the drainage criteria manual.
(b) 
Where the improvement or construction of a storm drainage facility is required along a property line common to two (2) or more owners, the owner proposing development of property shall be responsible for all required improvements on each side of the common property line, regardless of ownership, at the time of development, including the dedication by the legal owners of all necessary rights-of-way or easements to accommodate the improvements.
(c) 
Where a property owner proposes development of only a portion of the property, stormwater drainage facilities shall only be required in that portion of the property proposed for immediate development or use unless construction or improvement of a drainage facility outside that portion of the property is deemed essential to the development or use of that portion.
(d) 
The owner or developer shall provide adequate off-site drainage improvements to accommodate the full effects of the development. The owner or developer shall make adequate guarantees that she or he will finance the full cost of acquiring said property rights and shall retain full cost of acquiring said property rights and shall retain full responsibility for construction of the required off-site improvements.
(e) 
All detention basins and appurtenances which receive stormwater runoff from commercial or multifamily development shall be maintained by the record owner in accordance with the maintenance standards in the drainage criteria manual.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
Curbs and gutters shall be installed on all streets within an urban subdivision along lines and grades approved by the Engineering Department. All curbs and gutters shall comply with the drainage criteria manual.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
Enclosed storm sewers, bridges and culverts, designed in accordance with the drainage criteria manual, shall be installed by the applicant throughout the entire length of the drainage area within an urban subdivision. Plans and specifications shall be approved by the Engineering Department.
(Ordinance CO42-07-07-12-3I adopted 7/12/07)
Open drainage ditches in lieu of enclosed storm sewers are prohibited unless the Engineering Department has determined that the construction of open drainage ditches does not adversely affect the public health, safety, and general welfare.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)
No plans and specifications for any proposed alteration or improvement of a bed or bank of a waterway shall be accepted, reviewed or approved by the Engineering Department unless the plans are complete, accompanied by a certificate bearing the seal of a Texas-registered professional engineer certifying the adequacy of the design, hydraulically and structurally, of the proposed alteration or improvement and that the proposed alteration or improvement is in compliance with city ordinances, the drainage criteria manual, and state law; provided, however, this section shall not apply to plans and specifications for minor alterations and improvements which in the judgment of the Engineering Department do not require the services of a Texas-registered professional engineer.
(Ordinance CO11-20-01-09-H1 adopted 1/9/20)