When a property or project site is impacted by regulated riparian habitat (RRH), a permit application for construction is reviewed for avoidance of this habitat. Avoidance of disturbance to riparian habitat can be accomplished through applicant’s flexibility on the location of improvements on a project site. While the Riparian Ordinance prioritizes avoidance and minimization of disturbance to riparian habitat, there will be situations when impacts to riparian habitat cannot be avoided.
When a project disturbs more than a third of an acre of mapped regulated riparian habitat, mitigation is required. Here is some general information on the requirements:
There are three common ways to mitigate for residential property:
- On-site Mitigation
- In-lieu Fee
- Partial On-site and Partial In-lieu Fee
The three different options require a submittal of a Riparian Habitat Mitigation Plan (RHMP) which can be prepared by a plant professional (i.e. landscape architect or designer) or the homeowner can create an RHMP. It is always beneficial to contact a couple of professionals for availability and cost.
On-site mitigation consists of replacing a specific number of plants (trees, shrubs, and seeding) within a chosen mitigation area on the property. The required mitigation area must be 70% of the disturbed habitat.
Once the mitigation plantings are planted, there is a 5 year monitoring requirement where the property owner is required to submit photos and a brief report (letter) stating the health of the plantings; this can be done by a hired professional or the property owner. There is an 80% survivability requirement for the mitigation plantings. If the 80% success rate is not met at the end of five years, replacement mitigation plants will be required.
When the in-lieu fee option is chosen, there are three different methods to calculate the fee. Because there are not mitigation plantings associated with this option, the 5-year monitoring is not required.
The three different options are;
- Flat Fee Table: Applicant shall use the flat fee table for calculating the fee for acreage of disturbed Regulated Riparian Habitat (RRH), not mitigated onsite. Flat fee is based on cost per acre to mitigate onsite. The flat fee table accounts for all components of a mitigation plan.
- ILF Calculation Spreadsheet: The applicant may use the ILF calculation spreadsheet when certain components of the mitigation requirement are not completed onsite.
- ILF Cost Estimate Provided by a Qualified Professional: ILF cost estimates may be obtained from a qualified professional as an alternative to using the flat fee or spreadsheet calculations.
The revenue generated from the in-lieu fee(s) is deposited into an account the Pima County Flood Control District manages and used for remediation and revegetation of denuded Flood Control property and for purchasing land to set aside for open space and protection of riparian habitat and flood prone land.
Stay tuned for Part 3 the Riparian Habitat Disturbance and Violations: What You Need to Know…
This article was written by Patricia Gilbert, a Principal Hydrologist in Pima County, Arizona.