Status report on flood warning systems in the United States

One of the major changes in flash-flood mitigation in the past decade is the number of communities that have implemented warning systems. The authors conducted a survey of 18 early-warning systems in the United States developed by communities or regions to provide protection against flash floods or dam failures. Problems revealed by the study included the following: equipment malfunctions, inadequate maintenance funding, inconsistent levels of protection and expenditure, inconsistent levels of expectations and formalization, varying levels of local commitment to the systems, underemphasis on response capability, and a tendency to over-rely on warning systems. The study also revealed some unanticipated benefits experienced by the survey communities: the warning systems serve as valuable data collection tools, a great deal of interagency cooperation has been demonstrated, and warning systems offer increased alternatives to structural modification projects. The interjurisdictional nature of drainage basins, the evolving roles of the various federal agencies involved in flood mitigation, and the lack of governmental standards of operations for flood warning systems are issues that must be considered as communities make decisions regarding the adoption of warning systems. The record on these systems is too short for a precise assessment of how successful they are; however, results of the study indicate that if the goal of reducing loss of life and property from flooding is to be achieved, warning systems must be only one part of a comprehensive flood loss reduction program.     

Windows of change: temporal scale of analysis is decisive to detect ecosystem responses to climate change

Long-term ecological research has become a cornerstone of the scientific endeavour to better understand ecosystem responses to environmental change. This paper provides a perspective on how such research could be advanced. It emphasizes that a profound understanding of the mechanisms underlying these responses requires that records of ecologic processes be not only sufficiently long, but also collected at an appropriate temporal resolution. We base our argument on an overview of studies of climate impacts in limnic and marine ecosystems, suggesting that lakes and oceans respond to (short-term) weather conditions during critical time windows in the year. The observed response patterns are often time-lagged or driven by the crossing of thresholds in weather-related variables (such as water temperature and thermal stratification intensity). It becomes clear from the previous studies that average annual, seasonal or monthly climate data often fall short of characterizing the thermal dynamics that most organisms respond to. To illustrate such literature-based evidence using a concrete example, we compare 2?years of water temperature data from Müggelsee (Berlin, Germany) at multiple temporal scales (from hours to years). This comparison underlines the pitfalls of analysing data at resolutions not high enough to detect critical differences in environmental forcing. Current science initiatives that aim at improving the temporal resolution of long-term observatory data in aquatic systems will help to identify adequate timescales of analysis necessary for the understanding of ecosystem responses to climate change.     

The role of door orientation on occupant injury in a nearside impact: a CIREN, MADYMO modeling and experimental study

OBJECTIVE: This study addressed the effects of vehicle height mismatch in side impact crashes. A light truck or SUV tends to strike the door of a passenger car higher causing the upper border to lead into the occupant space. Conversely, an impact centered lower on the door, from a passenger car, causes the lower border to lead. We proposed the hypothesis that the type of injury sustained by the occupant could be related to door orientation during its intrusion into the passenger compartment. METHOD: Data on door orientation and nearside occupant injuries were collected from 125 side impact crashes reported in the CIREN database. Experimental testing was performed using a pendulum carrying a frame and a vehicle door, impacting against a USDOT SID. The frame allowed the door orientation to be changed. A model was developed in MADYMO (v 6.2) using the more biofidelic dummies, BIOSID, and SIDIIs as well as USDOT SID. RESULTS: In side impact crashes with the lower border of the door leading, 81% of occupants sustained pelvic injury, 42% suffered rib fractures, and the rate of organ injury was 0.84. With the upper border leading, 46% of occupants sustained pelvic injury, 71% sustained rib fracture, and the rate of organ injuries per case increased to 1.13. The differences in the groups with respect to pelvic injury were significant at p = 0.01, rib fracture, p = 0.10, and organ injury, p = 0.001. Experimental testing showed that when the door angle changed from lower to upper border leading, peak T4 acceleration increased by 273% and pelvic acceleration decreased by 44%. The model demonstrated that when the door angle changed from lower to upper border leading, the USDOT SID showed a 29% increase in T4 acceleration and a 57% decrease in pelvic acceleration. The BIOSID dummy demonstrated a 36% increase in T1 acceleration, a 44% increase in abdominal rib 1 deflection, a 91% increase in thoracic rib 1 deflection, and a 33% decrease in pelvic acceleration. CONCLUSIONS: These data add more insight to the problem of mismatch during side impacts, where the bumper of the striking vehicle overrides the door beam, causing the upper part of the door to lead the intrusion into the passenger compartment. Even with the same delta V and intrusion, with the upper border of the door leading, more severe chest and organ injuries resulted. This data suggests that door orientation should be considered when testing subsystems for side impact protection.