# A spatially explicit approach for identifying, prioritizing, and estimating costs associated with potential floodplain easements

## TL;DR

This study uses geospatial data to identify and prioritize floodplain easement opportunities in Iowa, estimating costs to guide conservation efforts and maximize ecosystem benefits.

## Contribution

A novel spatially explicit method for identifying and prioritizing floodplain easements while estimating restoration costs is developed.

## Key findings

- 2,707 high-priority floodplain easement locations were identified in Iowa.
- Estimated annual costs for restoring high-priority easements totaled 84.8 million USD.
- Restored floodplains can enhance ecosystem services like nutrient attenuation and habitat provision.

## Abstract

Over the past 150 years, land‐use changes from native ecosystems to row crop corn and soybeans have negatively impacted a variety of ecosystem services across the US Corn Belt, including nutrient attenuation, water storage, and habitat. Restoring floodplains in agriculturally dominated landscapes through United States Department of Agriculture Natural Resource Conservation Service programs (e.g., Emergency Watershed Protection program) could offer disproportionate opportunities to positively enhance ecosystem service benefits, yet identifying and prioritizing opportunities for conservation practices, including floodplain easements, to maximize environmental outcomes and financial resources remain challenging. This research sought to identify, prioritize, and evaluate costs associated with potential floodplain easements across the state of Iowa. Leveraging key geospatial data and criteria, including proportion of field within the 2‐ and 5‐year flood return interval, field boundaries, and land use characteristics, we identified 141,314 floodplain easement opportunities of which 2707 were identified as high‐priority locations based on the inundation frequency of the fields, representing a total area of 56,300 ha. To estimate acquisition, direct, and total costs associated with potential easements, we used soil and crop productivity index information, land value data, historic vegetation information, and partial enterprise budgets. Estimated costs to restore only high‐priority easement opportunities totaled nearly 84.8 million USD annually. This approach aimed to develop an accessible approach to assist natural resource practitioners and conservation planners in identifying, prioritizing, and estimating costs for potential floodplain easement locations across the state of Iowa and in other regions where data exist.

Suitable sites for floodplain easements were identified using geospatial technology.A prioritization score was assigned based on flooding frequency.Acquisition, direct, and total costs to restore suitable locations were estimated.The results aid in identifying high impact sites to effectively use limited funding.Restored floodplains provide habitat and attenuate nutrients and sediment.

Suitable sites for floodplain easements were identified using geospatial technology.

A prioritization score was assigned based on flooding frequency.

Acquisition, direct, and total costs to restore suitable locations were estimated.

The results aid in identifying high impact sites to effectively use limited funding.

Restored floodplains provide habitat and attenuate nutrients and sediment.

Land‐use changes from native ecosystems to row crop corn and soybeans have negatively impacted downstream ecosystems across the United States (US) Corn Belt. Floodplain restoration could offer opportunities to positively enhance ecosystem service benefits. This research sought to identify, prioritize, and evaluate costs associated with potential floodplain easement locations in Iowa. Utilizing geospatial data, suitability criteria, and land use characteristics, we identified 2,707 high priority floodplain easement locations in Iowa. To estimate costs associated with potential easements, we used soil productivity information, land value data, and partial enterprise budgets. Estimated costs to restore high priority easement opportunities totaled nearly 84.8 million USD annually. This approach could assist conservation planners in identifying, prioritizing, and estimating costs of potential floodplain easement locations.