River flood seasonality in the Northeast United States and trends in annual timing
Abstract
The New England and Mid-Atlantic regions of the Northeast United States have experienced climate-associated increases in both the magnitude and frequency of floods. However, a detailed understanding of flood seasonality across these regions, and how flood seasonality may have changed over the instrumental record, has not been established. The annual timing of river floods reflects the flood-generating mechanisms operating in a basin and many aquatic and riparian organisms are adapted to flood seasonality, as are human uses of river channels and floodplains. Changes in flood seasonality may indicate changes in flood-generating mechanisms, and their interactions, with important implications for habitats, floodplain infrastructure, and human communities. For example, changes in spring or fall flood timing may negatively or positively affect a vulnerable life stage for a migratory fish (e.g., egg setting) depending on whether floods occur more frequently before or after the life history event. In this study I apply an objective, probabilistic method for identifying flood seasons at a monthly resolution for 90 climate-sensitive watersheds in New England and the Mid-Atlantic (Hydrologic Unit Codes 01 and 02). Historical trends in flood timing during the year are also investigated. The analyses are based on partial duration flood series that are an average of 85 years long. The seasonality of flooding in these regions, and any historical changes, are considered in the context of other ongoing or expected phenological changes in the Northeast U.S. environment that affect flood generation—e.g., the timing of leaf-off/leaf-out for deciduous plants. How these factors interact will affect whether and how flood magnitudes and frequencies change in the future and associated impacts.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.H53D1472C
- Keywords:
-
- 1821 Floods;
- HYDROLOGY;
- 1869 Stochastic hydrology;
- HYDROLOGY;
- 4313 Extreme events;
- NATURAL HAZARDS;
- 4328 Risk;
- NATURAL HAZARDS