Estimation of Cropland Damages Caused by Overland Flooding, Two Case Studies

Abstract

Two case studies from Southern Ontario are descr bed in wh ch overland flooding in the early sprng caused extensive locaized erosional and otfrer damage to cropland Pedologic and economic appraisals of damages were undertaken. The extent of soils damage was evaluated from a survey of so ls and surface elevat ons along transects crossing the damaged zones. Baseline conditions were deterrnined from soilproftles in undisturbed areas. Soil samples were collected for an assessment of nutr ent content, pH levels and physical properties. Farrn operators using damaged and were interviewed to determine cropp ng patterns, rehabilrtation p ans for damaged ands and perceptions regardrng long-term impacts. Crop y elds n disturbed and und sturbed areas were deterrnined in the tollowing growing season. ln one case models were used to ascertain changes in the so I water regime and in yie d impacts under alternative weather conditions Yield reductions observed in the field for grains, corn and soybeans varied from .1 2 to 62 percent, while the modelling forecast a 4 to 51 percent grain corn yreld reduction in wet years and a 36 to 40 percent reduction n dry years. Rehabilitation plans for darnaged so ls were developed. These included and levelling, supp ementary tillage and herbicide applications, and the introduction of plowdown red clover. The total capitaltzed values o{ damages were estimated based on rehabilitation costs and lost crop revenues.

Remote Sensing Based Rapid Assessment of Flood Crop Damage Using Novel Disaster Vegetation Damage Index (DVDI)

“…Rapid assessment of flood-affected cropland acreage, however, can be helpful for early action to reduce the disaster risk. One very general approach for rapid flood crop loss assessment is to estimate the flooded acreage of cropland (Cressman et al 1988). A more specific approach than a general approach is crop-specific flooded acreage estimation (Citeau 2003;Dutta et al 2003;Zhu et al 2007;Förster et al 2008).…”