ABSTRACT: As watersheds are urbanized, their surfaces are made less pervious and more channelized, which reduces infiltration and speeds up the removal of excess runoff. Traditional storm water management seeks to remove runoff as quickly as possible, gathering excess runoff in detention basins for peak reduction where necessary. In contrast, more recently developed “low impact” alternatives manage rainfall where it falls, through a combination of enhancing infiltration properties of pervious areas and rerouting impervious runoff across pervious areas to allow an opportunity for infiltration. In this paper, we investigate the potential for reducing the hydrologic impacts of urbanization by using infiltration based, low impact storm water management. We describe a group of preliminary experiments using relatively simple engineering tools to compare three basic scenarios of development: an undeveloped landscape; a fully developed landscape using traditional, high impact storm water management; and a fully developed landscape using infiltration based, low impact design. Based on these experiments, it appears that by manipulating the layout of urbanized landscapes, it is possible to reduce impacts on hydrology relative to traditional, fully connected storm water systems. However, the amount of reduction in impact is sensitive to both rainfall event size and soil texture, with greatest reductions being possible for small, relatively frequent rainfall events and more pervious soil textures. Thus, low impact techniques appear to provide a valuable tool for reducing runoff for the events that see the greatest relative increases from urbanization: those generated by the small, relatively frequent rainfall events that are small enough to produce little or no runoff from pervious surfaces, but produce runoff from impervious areas. However, it is clear that there still needs to be measures in place for flood management for larger, more intense, and relatively rarer storm events, which are capable of producing significant runoff even for undeveloped basins. 相似文献
Environmental Science and Pollution Research - Gene-specific changes in DNA methylation by pesticides in occupationally exposed populations have not been studied extensively. Of particular concern... 相似文献
Objective: Alcohol-impaired driving is a significant factor in fatal and serious injury-producing crashes in the United States and many other countries. In 2013, the State of Maryland implemented an anti-driving under the influence (DUI) enforcement program, called the State Police Impaired Driving Reduction Effort (SPIDRE). This enforcement effort consisted of a select team of 7 police officers from the Maryland State Police who engaged in high-intensity driving under the influence (DUI) enforcement. The purpose of this evaluation was to determine the impact of the SPIDRE program on impaired-driving crashes, DUI arrests, DUI adjudicative outcomes, and public perceptions of DUI enforcement.
Methods: Data from alcohol-related crashes, arrests, and adjudicative outcomes of those arrests were used, along with data obtained from public opinion and bar patron surveys, to compare counties where the SPIDRE program operated and non-SPIDRE counties where it did not. The evaluation period extended from 2010 to 2016 in monthly intervals. Autoregressive integrated moving average (ARIMA) methods were used for the data analyses of crashes and arrests.
Results: There was no significant reduction in alcohol-related crashes as reported by the police associated with the SPIDRE program. However, there was a statistically significant decrease in the ratio of single-vehicle nighttime to multiple-vehicle daytime crashes in the SPIDRE counties but not in any other counties, suggesting a positive effect using this surrogate measure of impaired-driving crashes. The specific comparison counties as well as the other non-SPIDRE counties in Maryland experienced a statistically significant decrease in DUI arrests during the evaluation period, whereas the SPIDRE counties did not show such a decrease. Further, the arrests made by the SPIDRE team resulted in a significantly higher rate of positive adjudicative outcomes than arrests made by non-SPIDRE officers in those counties where the SPIDRE team operated. There was no evidence that the public was more aware of DUI enforcement efforts in the SPIDRE counties than in the non-SPIDRE counties.
Conclusions: The SPIDRE program appeared able to prevent a downward trend in DUI arrests, experienced by the rest of the state, and achieved higher quality arrests resulting in more positive adjudicative outcomes. The way in which the SPIDRE team was deployed may have lacked sufficient duration and intensity (e.g., only 2–3 months of activity in any given county) to achieve a reduction in alcohol-impaired-driving crashes as reported by the police. It is recommended that the SPIDRE team increase its enforcement activities for at least 9–12 consecutive months in the county where they are employed. 相似文献
Extreme weather and climate-related events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, dust storms, flooding rains, coastal flooding, storm surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden. More information is needed about the impacts of climate change on public health and economies to effectively plan for and adapt to climate change. This paper describes some of the ways extreme events are changing and provides examples of the potential impacts on human health and infrastructure. It also identifies key research gaps to be addressed to improve the resilience of public health to extreme events in the future.
Implications: Extreme weather and climate events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, flooding rains, coastal flooding, surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden. 相似文献
Salt marshes persist within the intertidal zone when marsh elevation gains are commensurate with rates of sea-level rise (SLR). Monitoring changes in marsh elevation in concert with tidal water levels is therefore an effective way to determine if salt marshes are keeping pace with SLR over time. Surface elevation tables (SETs) are a common method for collecting precise data on marsh elevation change. Southern New England is a hot spot for SLR, but few SET elevation change datasets are available for the region. Our study synthesizes elevation change data collected from 1999 to 2015 from a network of SET stations throughout Rhode Island (RI). These data are compared to accretion and water level data from the same time period to estimate shallow subsidence and determine whether marshes are tracking SLR. Salt marsh elevation increased at a mean overall rate of 1.40 mm year?1 and ranged from ?0.33 to 3.36 mm year?1 at individual stations. Shallow subsidence dampened elevation gain in mid-Narragansett Bay marshes, but in other areas of coastal RI, subsurface processes may augment surface accretion. In all cases, marsh elevation gain was exceeded by the 5.26 mm year?1 rate of increase in sea levels during the study period. Our study provides the first SET elevation change data from RI and shows that most RI marshes are not keeping pace with short- or long-term rates of SLR. It also lends support to previous research that implicates SLR as a primary driver of recent changes to southern New England salt marshes. 相似文献
An animal’s suitability as a biomonitor of environmental change can be determined by biological, reproductive and ecological
characteristics determined at the class, order and species level. The animal’s habitat where the research is to be performed
and the form, function and structure of the environmental change being studied within that habitat also determines suitability.
Non-threatened populations of large, non-migratory, long-lived, seasonally-breeding tertiary avian predators, whose dietary
preferences are narrow and known, can be useful as monitors of environmental chemical contaminants. If chemicals are being
monitored, a quantifiable endpoint effect must be demonstrated in the species, or a similar species under experimental laboratory
conditions. Logistical and economic issues as well as public and regulatory authority acceptance should also be considered
when assessing the suitability of a species as a biomonitor. 相似文献
Abstract: Both ground rain gauge and remotely sensed precipitation (Next Generation Weather Radar – NEXRAD Stage III) data have been used to support spatially distributed hydrological modeling. This study is unique in that it utilizes and compares the performance of National Weather Service (NWS) rain gauge, NEXRAD Stage III, and Tropical Rainfall Measurement Mission (TRMM) 3B42 (Version 6) data for the hydrological modeling of the Middle Nueces River Watershed in South Texas and Middle Rio Grande Watershed in South Texas and northern Mexico. The hydrologic model chosen for this study is the Soil and Water Assessment Tool (SWAT), which is a comprehensive, physical‐based tool that models watershed hydrology and water quality within stream reaches. Minor adjustments to selected model parameters were applied to make parameter values more realistic based on results from previous studies. In both watersheds, NEXRAD Stage III data yields results with low mass balance error between simulated and actual streamflow (±13%) and high monthly Nash‐Sutcliffe efficiency coefficients (NS > 0.60) for both calibration (July 1, 2003 to December 31, 2006) and validation (2007) periods. In the Middle Rio Grande Watershed NEXRAD Stage III data also yield robust daily results (time averaged over a three‐day period) with NS values of (0.60‐0.88). TRMM 3B42 data generate simulations for the Middle Rio Grande Watershed of variable qualtiy (MBE = +13 to ?16%; NS = 0.38‐0.94; RMSE = 0.07‐0.65), but greatly overestimates streamflow during the calibration period in the Middle Nueces Watershed. During the calibration period use of NWS rain gauge data does not generate acceptable simulations in both watersheds. Significantly, our study is the first to successfully demonstrate the utility of satellite‐estimated precipitation (TRMM 3B42) in supporting hydrologic modeling with SWAT; thereby, potentially extending the realm (between 50°N and 50°S) where remotely sensed precipitation data can support hydrologic modeling outside of regions that have modern, ground‐based radar networks (i.e., much of the third world). 相似文献
l-Aspartic acid was thermally polymerized in the presence of d-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred
when aspartic acid alone was heated at 170 or 200 °C. In contrast, heating sorbitol and aspartic acid neat or with ammonium
hydroxide gave a mixture of water soluble and insoluble copolymers of polysuccinimide and sorbitol. In the presence of phosphoric
acid, sorbitol aspartate ester copolymers having both water soluble and highly swollen gel components were formed. These results
indicate that polysaccharides such as sorbitol can readily react to form copolymer ester/amides with aspartic acid and such
copolymers may have utility as biodegradable water soluble and swellable polyampholytes. 相似文献