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11.
Quantifying Whitewater Recreation Opportunities in Cataract Canyon of the Colorado River,Utah: Aggregating Acceptable Flows and Hydrologic Data to Identify Boatable Days 下载免费PDF全文
The structural norm approach was combined with the Potential for Conflict Index to define recreation streamflow needs for the Colorado River in Utah and Colorado. An online survey was completed by 128 commercial and non‐commercial boaters, who evaluated a range of flows for whitewater boating. For the Cataract Canyon reach, respondents rated the quality of their recreation experience of specific flows, describing the quality of boating opportunities across the full range of historical streamflows. Ranges for both acceptable and optimum flows were defined, as well as thresholds for unacceptable flows. These ranges were then evaluated against historical hydrologic records to quantify the timing, frequency, and duration of days when defined whitewater flows exist across different year types (i.e. average boatable days). Results indicated that on average, a total of 257 boatable days existed in dry years, and 353 total boatable days occurred in dry‐typical years. In wet and wet‐typical years, 362 and 365 total boatable days respectively, occurred on average. Results of the boatable days' analysis indicated that over the 23‐year period of record, whitewater boating opportunities occurred nearly every day of the year in all but the driest year types. Results from this study provide resource managers with information which can be used in the development of annual operating plans for the Colorado River Basin and help managers understand how changes in flow impact the quality of recreational opportunities. This application demonstrates the value of analysing boatable days on any river where recreation management is a priority. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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在“三江并流”区内的怒江和澜沧江中、上游区域中新建小水电站,由于缺乏水文资料,径流计算中通用的水文比拟法不适用于此区域。过去通常采用径流深查图法,经电站建成运行后验证此方法计算的径流成果偏小。分析后提出在怒江及澜沧江双雨季地区的小水电站可采用新的径流计算方法一即水量平衡法,并结合具体工程验证其合理性。 相似文献
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天然气燃烧后无废渣、废水产生,相较煤炭、石油等能源具有使用安全、热值高、洁净等优势,在上海能源供应比例快速增长,已在能源供应中起到了举足轻重的作用.通过天然气供应系统可靠性分析以及天然气缺能经济损失的计算,提出了上海市天然气最优储备天数的分析方法,并以2011年为例进行了定量计算.分析结果显示,上海市天然气供应中断对经济损失影响较为稳定,但用来防止供应中断的天然气应急储备仍显不足. 相似文献
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The objective of this study was to use a within-cow, half-udder model to compare the effect of cessation of milk removal from mammary quarters within respective half udders at either 30 or 70 d before expected calving date (ECD) on the ability of the half udders to subsequently produce milk. Pregnant Holstein cows were assigned to control (n = 14) or treatment (TRT, n = 26) groups. All mammary quarters in the udder of cows in the control group had 70-d (68 ± 9 d) dry periods, whereas in each cow of the TRT group, 1 randomly selected half udder was dried at 70 d before ECD and the other half udder continued to be milked twice daily until dried at 30 d before ECD. From 80 through 70 d before ECD, amounts of milk produced by the left and right half udders of cows in the TRT group were measured at the first-shift milking. No differences were detected in the actual or relative amounts of milk produced by the left (3.46 ± 0.2 kg; 48.8 ± 1.0%) and the right (3.63 ± 0.2 kg; 51.2 ± 1.0%) half udders. Furthermore, the actual and relative amounts of milk produced by the half udders (n = 12 left, 14 right) subsequently dry for 67 ± 7 d (3.56 ± 0.2 kg; 50.2 ± 1.0%) and the half udders (n = 14 left, 12 right) subsequently dry for 27 ± 7 d (3.54 ± 0.2 kg; 49.8 ± 1.0%) did not differ before they were dried. However, from 3 to 100 d of the subsequent lactation, the 30-d dry half udders produced 18.9% less milk than the 70-d dry half udders (16.3 vs. 20.1 ± 1.0 kg/d). In addition, relative amounts of total-udder milk produced by the 30- and 70-d dry half udders in the same cow differed (44.9 vs. 55.1 ± 0.2%, respectively). Cows in the control group produced more milk than cows in the TRT group through 80 DIM (39.5 vs. 35.2 ± 0.6 kg/d), but not from 3 through 150 DIM (39.0 vs. 36.2 ± 1.6 kg/d). Thus, half udders that produced the same actual and relative amounts of milk before being dried did not do so when given a 30-d dry period instead of a 70-d dry period. When compared with the pre-dry value (49.8%), the relative contribution of half udders dry for 30 d to the total milk yield during the first 100 DIM was decreased by 9.8%. 相似文献
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国有企业的物资储备资金,既是保证企业生产经营正常进行的前提,又是加速流动资金周转的必要条件。要把企业储备资金的定额指标真正“量化”,并落实到物资品种上,就应该有正确的核算方法。葫芦岛锌厂的实践证明,统计核算法能够适应国企对储备资金定额的科学管理。 相似文献
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讨论了基于相似日选取的支持向量机电动汽车日负荷预测方法。通过对北京现有纯电动公交车充/换电站充电负荷的大量调研,分析了公交车充电站充电负荷的数据特征,采用关联分析方法提取了影响电动公交站充电负荷的因素,基于相关因素应用灰色关联理论构建相似日的小样本集合,而后建立多输入单输出的支持向量机预测模型。针对支持向量机预测模型,提出了两阶段确定模型参数的方法,首先直接确定不敏感损失参数ε,再通过遗传算法寻找最优核参数p和正则化参数C,以提高参数ε选取范围设置较大时的预测精度。实例测试结果表明,日负荷预测的均方根误差为10.85%,能基本满足有序控制的要求;与其他预测方法相比,改进方法具有较高的预测精度和稳定性。 相似文献
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In this paper, we describe a method for constructing regional electricity demand data sets at 30 min intervals, which are consistent with climate change scenarios. Specifically, we modify a commonly used linear regression model between regional electricity demand and climate to also describe intraday variability in demand so that regional load duration curves (LDCs) can be predicted. The model is evaluated for four different Australian states that are participants in the Australian National Electricity Market (NEM) and the resultant data sets are found to reproduce each state's LDCs with reasonable accuracy. We also apply the demand model to CSIRO's Mk 3 global climate model data sets that have been downscaled to 60 km resolution using CSIRO's conformal-cubic atmospheric model to estimate how LDCs change as a consequence of a 1 °C increase in the average temperature of Australian state capital cities. These regional electricity demand data sets are then useful for economic modelling of electricity markets such as the NEM. 相似文献
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