A. Purpose: The purpose of regulating development in and around stream corridors is to:
1. Preserve the value of stream corridors in providing floodwater conveyance and storage;
2. Promote filtration of storm water runoff;
3. Reduce stream bank erosion; and
4. Protect and enhance wildlife habitat.
B. Stream Corridor Regulation By Other Agencies: The approval of a sensitive areas development plan shall be in addition to the applicant's need to obtain permits required by other local, state or federal agencies, and does not alter the applicant's obligation to satisfy and obtain all other applicable local, state or federal regulations and permits.
C. Environmental Review Required: A sensitive areas development plan for property containing a regulated stream corridor must include evidence demonstrating that all regulations of this section will be met. Such plan must include the following information: (Ord. 05-4186, 12-15-2005)
1. A delineation of the stream corridor and the required natural buffer area is required. If, in the course of delineating a blue line stream, it is determined through field verification by a qualified professional, such as a geologist, hydrologist, or wetland specialist, that the blue line or a portion of a blue line on the current U.S. geological survey quadrangle maps does not represent a watercourse with a bed and bank defined by an "ordinary high water mark", as defined herein, and a definite direction of flow, either continuously or intermittently, then said watercourse or portion of a watercourse will not be considered a regulated stream corridor for purposes of this title. In such an event, a report prepared by said qualified professional must be submitted to the city that demonstrates to the satisfaction of the city that the subject watercourse does not have the aforementioned defining characteristics of a stream corridor. (Ord. 10-4398, 7-12-2010)
2. Delineation of a construction area limit and specification of associated restrictions thereof.
3. Information regarding the characteristics of the stream corridor necessary to determine the allowable buffer reduction as provided in subsection D, "Stream Corridor Buffer Requirements", of this section if a reduction is requested.
D. Stream Corridor Buffer Requirements:
1. Unless exempt pursuant to subsection 14-5I-2C, "Exemptions", of this article, the following natural buffers must be maintained along regulated stream corridors. When other regulated sensitive features are located within a stream corridor, a fifty foot (50') buffer is required.
a. Along the Iowa River, a fifty foot (50') natural buffer must be maintained between any development activity and the stream corridor, which includes the floodway.
b. Along tributaries to the Iowa River that have a delineated floodway, a thirty foot (30') natural buffer must be maintained between any development activity and the stream corridor, which includes the floodway. These tributaries include, but are not limited to, Ralston Creek, Willow Creek, Snyder Creek, Clear Creek and Rapid Creek.
c. Along tributaries or drainageways that do not have a delineated floodway, a fifteen foot (15') natural buffer must be maintained between any development activity and the stream corridor limits.
2. The applicant may request a reduction of the required natural buffer in certain circumstances enumerated below:
a. The required natural buffer may be reduced by up to fifty percent (50%) if the applicant demonstrates that the portion of the buffer being reduced:
(1) Does not contain significant existing vegetative cover, such as native trees or prairie remnants; and
(2) Does not contain other sensitive areas subject to the requirements of this article; and
(3) Enhanced vegetative cover will be provided in the remaining buffer area.
b. The required natural buffer may be reduced by up to one hundred percent (100%) if the applicant demonstrates that:
(1) The property is adjacent to or contains a stream corridor located in a "developed area of the city"; and
(2) The portion of the buffer being reduced does not contain other sensitive areas subject to the requirements of this article; and
(3) Requiring the full stream corridor buffer would preclude reasonable use of the property; and
(4) Enhanced vegetative cover will be provided in any remaining buffer area, to the extent possible.
c. In addition to the qualifying criteria listed above, the city will consider the following factors in determining whether to reduce the required buffer:
(1) The proposed land use of the property and its potential impact on the stream corridor;
(2) The design and layout of the proposed development in relation to the stream corridor;
(3) The characteristics of the site and the stream corridor; and
(4) Any other factors related to the short or long term environmental stability and health of the stream corridor. (Ord. 05-4186, 12-15-2005)