A. Purpose: The purpose of regulating development in and around wetlands is to:
1. Preserve the unique and valuable attributes of wetlands as areas where storm water is naturally retained, thereby controlling the rate of runoff, improving water quality, recharging ground water resources, providing erosion control and lessening the effects of flooding;
2. Promote the preservation of habitat for plants, fish, reptiles, amphibians or other wildlife;
3. Minimize the impact of development activity on wetland areas;
4. Provide a greater degree of protection for many wetland areas above and beyond that provided by the federal and state government; and
5. Minimize the long term environmental impact associated with the loss of wetlands.
B. Wetland Regulation By Other Agencies: The approval of a sensitive areas development plan under the provisions of this article is 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. Wetland Mitigation Plan Required:
1. A sensitive areas development plan for property containing a regulated wetland shall include a wetland mitigation plan demonstrating that all regulations of this section will be met. Avoiding a delineated wetland area and minimizing the impact of development on a wetland is strongly encouraged, and must be investigated before compensatory mitigation will be considered.
2. A wetland mitigation plan shall include the following information:
a. The boundaries of the delineated wetland and the required natural buffer area.
b. Delineation of a construction area limit and specification of associated restrictions thereof.
c. The type and location of erosion control measures to be placed on the property prior to any other development activity occurring on the site.
d. Certification by a wetland specialist or the U.S. army corps of engineers, or its successor, regarding the wetland delineation, if required.
e. Information regarding the characteristics of the wetland necessary to determine the allowable buffer reduction as provided in subsection E, "Wetland Buffer Requirements", of this section if a reduction is requested.
f. A storm water management plan demonstrating compliance with the requirements of the Iowa City storm water regulations and related municipal design standards.
D. Wetland Delineation:
1. Prior to any development activity occurring on a site containing a potential regulated wetland, the property owner must provide a delineation of the wetland area. Determination of jurisdictional wetlands must be made either by the U.S. army corps of engineers, or its successor, or by a wetland specialist. If completed by a wetland specialist, the wetland delineation must be reviewed and accepted by the U.S. army corps, or its successor. Delineation of wetland areas must be completed prior to the submittal of a sensitive areas development plan for review.
2. If the property owner certifies that no development activity will occur within one hundred fifty feet (150') of the apparent edge of a suspected or potential wetland area on the site, the requirement for delineation by a wetland specialist or the corps may be waived by the city. In the case of a waiver, the property owner shall grant an easement running in favor of the city, an approved conservation group, or other approved organization for the purpose of retaining the wetland and the surrounding one hundred fifty foot (150') protection area as undeveloped natural open space.
E. Wetland Buffer Requirements:
1. An undisturbed, one hundred foot (100') natural buffer shall be maintained between any development activity and a regulated wetland unless said development activity is exempted pursuant to subsection 14-5I-2C, "Exemptions", of this article. The required setbacks established for the base zone shall be measured from the buffer edge, and are in addition to the required buffer. This setback requirement applies to parking lots as well. (For example, the RS-5 district requires a 20 foot rear setback, which would be measured from the outside edge of the required 100 foot buffer. As a result, no building or parking lot could be located within 120 feet of the wetland.)
2. Buffer averaging may be permitted or required where an increased buffer is deemed necessary or desirable to provide additional protection to one area of a wetland for aesthetic or environmental reasons. In this situation, the width of the required buffer around other areas of the wetland may be reduced by up to fifty percent (50%), but the area of the provided buffer must be equal to or greater than the total area of the required buffer. Any request for buffer averaging requires a level II sensitive areas review. Buffers that have been reduced according to the provisions of subsection E3 of this section may not be averaged.
3. The applicant may request a reduction of the required natural buffer in certain instances enumerated below. Any request for a reduction in the natural wetlands buffer requires a level II sensitive areas review. Buffers that have been averaged according to the provisions of subsection E2 of this section may not be reduced.
a. The required natural buffer may be reduced by up to fifty feet (50') if it can be demonstrated by a wetland specialist that the wetland:
(1) Is less than five (5) acres in area; and
(2) Does not contain species listed by the federal or state government as endangered or threatened, or critical or outstanding natural habitat for those species; and
(3) Does not contain diverse plant associations of infrequent occurrence or of regional significance; and
(4) Is not located within a regulated stream corridor.
b. The required natural buffer may be reduced by up to seventy five feet (75') if it can be demonstrated by a wetland specialist that the wetland:
(1) Satisfies the criteria for natural buffer reduction in subsection E3a of this section; and
(2) Does not, in a year of average precipitation, contain standing water at any time during the calendar year; and
(3) Is not a forested wetland; and
(4) Does not provide a known habitat for migratory birds of local or regional significance.
c. In addition to the qualifying criteria listed above, the city shall consider the following factors in determining whether or not to reduce the required buffer:
(1) The proposed land use of the property and its potential impact on the wetland; and
(2) The design and layout of the proposed development in relation to the wetland; and
(3) The physical characteristics of the site and the wetland; and
(4) Any other factor related to the short or long term environmental stability and health of the wetland.
F. Design Standards:
1. No grading, dredging, clearing, filling, draining, or other development activity is allowed within a regulated wetland or required buffer area, unless said activity is part of an approved wetland mitigation plan or is a use, activity or structure allowed according to subsection 14-5I-2D, "Uses, Activities And Structures Allowed Within Protected Sensitive Areas", of this article.
2. For property not served by a city sanitary sewer system, the location of septic tanks, soil absorption systems, holding tanks, or any other element of an on site sewage disposal system must meet the required setbacks specified in the base zone, as measured from the buffer edge.
3. To mitigate negative impacts of development and limit sedimentation, the direct discharge of untreated surface water from a development site or a developed area into a wetland may be prohibited. The partial treatment of storm water runoff through the use or combined use of constructed wetlands, detention basins, vegetative filter strips, sediment traps or other means before the storm water runoff reaches a wetland may be considered as part of a wetland mitigation plan. In such case, the discharge should not increase the rate of flow or decrease the water quality of the wetlands unless it can be shown by a wetland specialist that an increase in the rate of flow will enhance rather than adversely impact the wetland.
4. On any lot containing a regulated wetland, erosion control measures, whether required under title 17, chapter 8, "Grading Ordinance", of this code, or as part of a wetland mitigation plan approved under the provisions of this article, must be installed prior to any development activity occurring on the site.
5. The planting of foreign or invasive species, including intrusive native varieties, in regulated wetland or buffer areas is prohibited. Only nonintrusive native species shall be used to supplement existing vegetation.
6. The removal of foreign or invasive species, including intrusive native varieties, within a regulated wetland or buffer area may be permitted when approved as part of an approved wetland mitigation plan.
7. Where it is determined that the area occupied by the required buffer provides little natural protection to the wetland due to previous land disturbance, enhanced vegetative cover must be provided within the buffer area to help filter and slow the flow of surface water. The enhanced vegetation shall consist of species that are known to be noninvasive to wetland areas.
G. Compensatory Mitigation: Compensatory mitigation may be permitted only if it is clearly demonstrated that avoiding and minimizing the impact on a wetland is unreasonable. A permit for any development activity within a wetland area is required by the U.S. army corps of engineers or its successor. If a permit is granted for development activity within a wetland, compensatory mitigation shall be required based on the following criteria, unless a greater degree of compensation is required by the corps or its successor:
1. Wetlands containing the following characteristics shall be considered protected, "no build" wetland areas. Compensatory mitigation will be considered only if the wetland disturbance is relatively small in relation to the overall wetland and if it can be shown that the disturbance will not have an adverse impact on the overall wetland. In wetlands with the following characteristics, if compensatory mitigation is permitted, the required replacement ratio of comparable habitat replaced to habitat lost shall be at least three to one (3:1):
a. Wetlands containing species listed by the federal or state government as endangered or threatened, or containing critical or outstanding natural habitat for those species; or
b. Wetlands containing the presence of diverse plant associations of infrequent occurrence or of regional importance; or
c. Wetlands located within regulated stream corridors as defined in this article.
2. The replacement ratio of comparable habitat replaced to habitat lost shall be at least two to one (2:1) for wetlands not containing the characteristics listed in subsection G1 of this section, but which do contain the following characteristics:
a. Standing water throughout the calendar year under average precipitation;
b. Forested wetlands; or
c. Wetlands providing a known habitat for migratory birds of regional or local significance.
3. Compensatory mitigation for all other regulated wetlands shall be at a ratio of at least one to one (1:1). If said wetland or the replacement habitat is enhanced so that it contains one or more of the defining characteristics listed in subsection G1 or G2 of this section, the required replacement ratio may be reduced to 0.5:1.
4. When compensatory mitigation is proposed, the wetland mitigation plan described in this section must be prepared by a wetland specialist. A wetland mitigation plan that includes compensatory mitigation must include the following components:
a. An assessment of the value of the wetland being replaced to determine the appropriate replacement ratio;
b. A clear statement of the goals of the mitigation plan, including specific statements regarding the expected rate of establishment of a vegetative cover over specified periods of time;
c. Analysis of the soils, substrate and hydrology of the proposed site of the constructed or expanded wetland in terms of their suitability to provide a proper growing medium for the proposed vegetation;
d. A list of the plant species to be used, which should include only native, noninvasive species, and their proposed locations. Transplanting as much of the native vegetation from the original wetland as possible, as well as the upper six (6) to twelve inches (12") of the soil is encouraged; and
e. Provisions for monitoring the condition of the new or enhanced wetland area for a period of five (5) years, and identification of the party responsible for replanting in the event of poor initial growth or predation resulting in a failure of over thirty percent (30%) of the planted stock. Information collected during the monitoring process must be submitted to the city annually and include the following:
(1) Data on plant species diversity and the extent of plant cover established in the new or enhanced wetland;
(2) Wildlife presence;
(3) Data on water regimes, water chemistry, soil conditions and ground and surface water interactions; and
(4) Proposed alterations or corrective measures to address deficiencies identified in the created or enhanced wetland, such as a failure to establish a vegetative cover or the presence of invasive or foreign species. (Ord. 05-4186, 12-15-2005)