干旱荒漠区油田开发与生态系统服务功能研究

根据干旱荒漠区域自然条件、社会经济条件和资源状况的总体特征,明确其生态环境特征、生态系统服务功能、生态环境功能重要性与敏感性的空间分异规律,确定区域生态功能分区,为制定油田开发生态环境保护与建设规划、维护区域生态安全、促进社会经济可持续发展提供科学依据。     

森林对径流影响研究的回顾与展望

论文简要回顾了森林水文学的研究历史，并重点介绍了在森林水文学研究中居于重要地位的森林集水区研究的起源与发展，分析了这一研究方法的特点，并对主要研究结果进行了比较。大多数研究结果显示，去除森林可以使径流量增加，但森林与水的关系极其复杂，森林对径流量的影响因地域、森林类型以及森林管理方式等因素的不同而存在差异；在评价森林对流域径流量的影响时应全面考虑，分析各地区之间的差别，一个地区所得的结果不能作为森林生态系统水文功能的普遍规律而在其它条件不同的地区加以应用。今后应加强合作研究，特别是利用网络研究对比不同集水区之间的结果来探讨森林对径流的影响，同时重视新技术和新方法的应用。     

塔里木沙漠石油公路风沙危害

为了给沙漠石油公路防沙工程设计和未业公路养护提供科学依据,综合野外观测及风洞模拟实验资料,分析了塔里木沙漠石油公路风沙危害的形成,建立了风沙危害程度的评价模式,从而得出公路沿线的风沙危害具有如下时空分布规律：（１）在时间上,风沙危害主要集中于春、夏季节（４－９月）,其中４月份最强;（２）在空间上,愈向沙漠深入,风沙危害愈烈,风沙危害程度指数的理论估算值与风沙现象观测记录相吻合。     

沙漠环境特点及其对工程装备的影响

介绍了国内典型沙漠环境的特点,分析了其对工程装备的主要影响和危害,从装备论证、研制、设计定型和使用等全寿命周期提出了增强工程装备沙漠环境适应性所需要采取的措施。     

降雨变化对荒漠草原植物群落多样性与土壤C:N:P生态化学计量特征的影响

研究降雨格局变化对植物群落多样性、土壤C：N：P生态化学计量特征的影响,以及关键土壤因子与植物群落多样性间的关系,对于荒漠草原植物群落多样性的保护具有重要意义.本文以黄土高原西部荒漠草原为研究对象,通过3 a野外降雨控制试验（减少40%降雨、减少20%降雨、自然降雨、增加20%降雨和增加40%降雨）,探讨干湿年份下降雨变化对植物群落多样性及其土壤C：N：P生态化学计量特征的影响,以及降雨变化下土壤C：N：P生态化学计量特征及关键土壤因子与植物群落多样性的关系.结果表明,在正常年份与偏干年份（2013年与2015年）,Patrick丰富度和Shannon-Wiener多样性指数分别以减雨20%处理显著低于对照和增雨40%处理,在偏湿年份（2014年）,Patrick丰富度和Shannon-Wiener多样性指数对降雨处理无显著差异.在正常年份与偏干年份,随降雨量的增加土壤有机碳（SOC）、全氮（TN）、全磷（TP）、碳氮比（C：N）、碳磷比（C：P）和氮磷比（N：P）呈降低趋势,其中,C：N显著降低;在偏湿年份,随降雨量增加土壤SOC、TN、C：P和N：P呈上升趋势.在正常年份,降雨处理对土壤含水量影响不显著,导致土壤含水量对植物群落影响有限,SOC、TN、N：P、C：N和微生物量氮（MBN）对植物群落多样性的影响更为突出;在偏湿年份,年降雨量丰富,降雨量增加导致土壤养分上升,水分不是限制植物生长的最重要因素,土壤含水量、土壤养分与生态化学计量特征共同调节和控制着植物群落多样性;在偏干年份,降雨处理对土壤含水影响显著,且降雨量增加导致土壤养分流失较多,因此,土壤含水量成为影响植物群落多样性的最主要因素.由此可知,在不同干湿年份,植物群落多样性与土壤C：N：P生态化学计量特征对降雨变化的响应不同;土壤C：N：P对植物群落多样性的影响也不同,本文的研究结果旨在为未来降雨变化下荒漠草原的保护与管理提供一定的理论依据.     

Predicting the effects of urbanization on runoff after frequent rainfall events

Urbanization dynamics are commonly subjected to powerful market forces, only partly managed by land-use plans. The density, location and pattern of urbanized areas affect rainfall-runoff relations. Consequently, it is essential to understand future impacts of urbanization on runoff and produce focused regulation. The goal was to analyze land-cover scenarios and their impact on runoff in an urbanized watershed in Israel. Present and predicted land-cover scenarios in a densely populated watershed were produced. The runoff response to rainfall was then simulated using a hydrological model. The impact of implementing afforestation and quarrying national outline plans was considered. By the year 2050, 50% of the watershed will be urbanized with a linear increase in runoff response. Afforestation and quarrying plans show little effect on runoff, although quarries may decrease runoff through percolation. As urbanization is expected to continue spreading in adjacent watersheds, statutory measures should be applied to mitigating runoff.     

USING FIELD SCALE MODELS TO PREDICT PEAK FLOWS ON AGRICULTURAL WATERSHEDS1

The goal of this study was to develop a methodology for generating storm hydrographs at a watershed scale based on daily runoff estimates from a field scale model. The methodology was evaluated on a small agricultural watershed using the ADAPT field scale process model. A comparison of observed and predicted peak flows for 11 of the largest events that occurred in a three year period gave r² values of 0.84, 0.82, and 0.81 when the watershed was subdivided into 1, 5, and 10 sub watersheds. However, all other statistical measures improved when the watershed was subdivided into at least five sub watersheds. Guidelines need to be developed on the use of the procedure but it first needs to be evaluated on several watersheds that exhibit a range in sizes, land uses, slopes, and soil properties.     

POTENTIAL CLIMATE CHANGE IMPACTS ON MOUNTAIN WATERSHEDS IN THE PACIFIC NORTHWEST1

ABSTRACT: Global climate change due to the buildup of greenhouse gases in the atmosphere has serious potential impacts on water resources in the Pacific Northwest. Climate scenarios produced by general circulation models (GCMs) do not provide enough spatial specificity for studying water resources in mountain watersheds. This study uses dynamical downscaling with a regional climate model (RCM) driven by a GCM to simulate climate change scenarios. The RCM uses a subgrid parameterization of orographic precipitation and land surface cover to simulate surface climate at the spatial scale suitable for the representation of topographic effects over mountainous regions. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO₂ concentration. The RCM results indicate an average warming of about 2.5°C, and precipitation generally increases over the Pacific Northwest and decreases over California. These simulations were used to drive a distributed hydrology model of two snow dominated watersheds, the American River and Middle Fork Flathead, in the Pacific Northwest to obtain more detailed estimates of the sensitivity of water resources to climate change. Results show that as more precipitation falls as rain rather than snow in the warmer climate, there is a 60 percent reduction in snowpack and a significant shift in the seasonal pattern of streamflow in the American River. Much less drastic changes are found in the Middle Fork Flathead where snowpack is only reduced by 18 percent and the seasonal pattern of streamflow remains intact. This study shows that the impacts of climate change on water resources are highly region specific. Furthermore, under the specific climate change scenario, the impacts are largely driven by the warming trend rather than the precipitation trend, which is small.     

EFFECTS OF INTERANNUAL VARIATION OF PRECIPITATION ON STREAM DISCHARGE FROM RHODE RIVER SUBWATERSHEDS1

ABSTRACT: The purpose of this study was to determine the relationships between precipitation at the seasonal and annual scale and water discharge per surface area for seven contiguous first - and second-order tributaries of the Rhode River, a small tidal tributary to Chesapeake Bay, Maryland, USA. The goal was to quantify the effects of a wide range of precipitation, representative of inter-annual variations in weather in this region. The discharges measured included both overland storm flows and groundwater, since the aquifers were perched on a clay aquiclude. Precipitation varied from 824 to 1684 mm/yr and area-weighted Rhode River watershed discharge varied from 130 to 669 mm/yr with an average of 332 mm/yr or 29.1 percent of average precipitation. Average annual dis. charges from three first-order watersheds were significantly lower per surface area and varied from 16.0 to 21.9 percent of precipitation. Winter season precipitation varied from 125 to 541 mm. Area-weighted Rhode River winter discharge varied from 26.3 to 230 mm with an average of 115 mm or 43.9 percent of average precipitation. Spring season precipitation varied from 124 to 510 mm and watershed discharge varied from 40.0 to 321 mm with an average of 138 mm or 46.9 percent of average precipitation. In the summer and fall seasons, watershed discharge averaged 40.6 and 40.9 mm or 13.5 and 14.3 percent of average precipitation, respectively. Except in winter, the proportion of precipitation discharged in the streams increased rapidly with increasing volume of precipitation. Stream order showed a higher correlation with volume of discharge than vegetative cover on the watershed.     

ESTIMATING ATRAZINE LEACHING IN THE MIDWEST1

Data from seven Management Systems Evaluation Areas (MSEA) were used to test the sensitivity of a leaching model, Pesticide Root Zone Model-2, to a variety of hydrologic settings in the Midwest. Atrazine leaching was simulated because it was prevalent in the MSEA studies and is frequently detected in the region's groundwater. Short-term simulations used site specific soil and chemical parameters. Generalized simulations used data avail. able from regional soil databases and standardized variables. Accurate short-term simulations were precluded by lack of antecedent atrazine concentrations in the soil profile and water, suggesting that simulations using data for less than five years underestimate atrazine leaching. The seven sites were ranked in order of atrazine detection frequency (concentration > 0.2 μg L^-1) in soil water at 2 m depth in simulations. The rank order of the sites based on long-term simulations were similar to the ranks of sites based on atrazine detection frequency from groundwater monitoring. Simulations with Map Unit Use File (MUUF) soils data were more highly correlated with ranks of observed atrazine detection frequencies than were short-term simulations using site-specific soil data. Simulations using the MIJUIF data for soil parameters were sufficiently similarity to observed atrazine detection to allow the credible use of regional soils data for simulating leaching with PRZM-2 in a variety of Midwest soil and hydrologic conditions. This is encouraging for regional modeling efforts because soil parameters are among the most critical for operating PRZM-2 and many other leaching models.