CHANGING WATER BALANCE OVER TIME IN RUSH CREEK,EASTERN CALIFORNIA, 1860–19921

ABSTRACT: Rush Creek, the principal tributary to Mono Lake, has undergone profound hydrologic modifications as a result of flow regulation for hydroelectric generation and irrigation, diversions for irrigated agriculture, and diversions for water export to the City of Los Angeles. Lower Rush Creek (the lowermost 13 km downstream of Grant Lake Reservoir) was dry by 1970, but now receives flow as a result of court-ordered efforts to restore former ecological conditions. Using available historic data and recent field measurements, we constructed the water balance for Lower Rush Creek, identifying six distinct historical periods characterized by very different patterns of gain and loss. The hydrologic patterns must be understood as a basis for modeling ecosystem response to stream-flow alteration. A gradually gaining stream under natural conditions, the advent of irrigation diversions caused the middle reaches of Lower Rush Creek to be often completely dry, while irrigation-recharged springs still maintained a baseflow in the downstream “Meadows” ranch. Increased water exports from the basin subsequently reduced irrigation and dried up the springs.     

Scientific certainty and the laws that govern location of a potential high-level nuclear waste repository

Recent studies have questioned the ability of the Department of Energy to successfully construct and operate a high-level nuclear waste repository at Yucca Mountain, Nevada, USA, consistent with current Environmental Protection Agency standards and Nuclear Regulatory Commission regulations. Questions focus on whether demonstration of compliance with the agency's standards is based too much on numerical calculations and analyses that the Department of Energy must conduct to project the long-term performance of the repository. Unless these questions are resolved, the licensing of the repository could be withheld or delayed by litigation. This article reviews the extent to which laws that govern the siting of high-level nuclear waste repositories require scientific certainty in any findings about the environmental consequences of locating a repository.     

AN ANALYSIS OF PLAYA LAKE WATER UTILIZATION ON THE TEXAS HIGH PLAINS1

ABSTRACT: This paper examines the spatial, temporal and legal aspects of playa lake water utilization on the semi-arid Texas High Plains. These small basins of interior drainage collect and briefly hold an estimated two to three million acre-feet of runoff water annually, representing from one-fourth to one-third the quantity of groundwater pumped from the dwindling Ogallala aquifer. Once considered a detriment to farming operations, there is now increased interest in using playa water more effectively. At present direct pumping is the chief method of utilization, and modification of lake bottoms to concentrate runoff and reduce evaporation is the most widespread conservation practice. The use of playa water for groundwater reacharge is hampered by as yet unsolved technical problems. For many years the question of ownership of playa water remained unsettled. The Texas Water Rights Commission now classes it as diffused surface water, which under Texas law may be used by the landowner, though some legal problems remain. For play lakes to be effectively integrated into the regional water resource it becomes imperative that all present and prospective water utilization problems be identified and resolved.     

PROBLEMS OF PUBLIC ACCESS TO WATER IN TEXAS LAKES AND STREAMS1

ABSTRACT: Rapidly increasing demand for recreational use of Texas' public waters is resulting in growing conflict between riparian landowners and the public. This paper examines the public access question, certainly one of the most poorly defined and understood areas of Texas water and property law. Since the appropriation acts of the late 1800's, most surface waters are owned by the state, and are held in trust for the benefit of the people. While there is no express statutory authority giving the general public the right to use these waters, there is extensive, if often conflicting, case law recognizing such rights on navigable streams. It is equally well established that the public may not gain access by crossing private property. Definition of public and private rights is complicated by the fact that Texas land grants (with their attendant property rights) have emanated from Spain, Mexico, the Republic of Texas, and the state. Obstacles imposed by riparian landowners to public entry, use and passage, as well as spatial aspects of access, are also considered. Because public access rights are based on the peculiar circumstances of each case, it is difficult to establish general legal principles, and there is almost no reliable information to aid the recreation-seeking public. A clear legislative enunciation of public rights appears politically infeasible at present, the most immediately attainable goal lying in the area of better public education.     

EFFECTS OF WOODY VEGETATION ON SANDY LEVEE INTEGRITY1

he influence of woody vegetation on the reliability of a sandy levee was investigated using field data in seepage and slope stability analyses. Field data were collected from selected sites within a 10-km segment of a channel levee on the Sacramento River near Elkhorn, California. Root architecture and distribution were determined using the profile-wall method in which root cross sections were exposed in the vertical wall of an excavated trench. Transects running both parallel and perpendicular to the crest of the levee were excavated at six sites. Each site was dominated by different plant species: five sites were adjacent to trees or woody shrubs, while one supported only herbaceous growth. Lateral plant roots were primarily restricted to, and modified, the near-surface soil horizons to a depth of approximately 1 meter. Root area ratios (RARs) did not exceed 2.02 percent and generally decreased exponentially with depth. At depths greater than 20 cm, mean RARs for sites dominated by wood species were not significantly different from the mean RAB for the herbaceous site. No open voids clearly attributable to plant roots were observed. Roots reinforced the levee soil and increased shear resistance in a measurable manner. Infinite slope and circular arc stability analyses were performed on the landward and riverward slopes under different hydraulic loading conditions. Infinite slope analyses indicated increasing root area ratio from 0.01 percent to 1 percent increased the factor of safety from less than one to more than seven. Circular arc analyses indicated that even the lower measured root concentrations sufficed to increase safety factors for arcs with maximum depths of about 1 m from less than one to about 1.2. Our findings suggest that allowing woody shrubs and small trees on levees would provide environmental benefits and would enhance structural integrity without the hazards associated with large trees such as wind-throwing.     

对于环境执法监管中的几点建议

针对温总理在2006年全国环境保护大会上提到的现阶段环境执法存在的问题，提出了尽快完善环境法规体系，建立环境执法管理制度；建立完善的领导干部环保政绩考核制度。彻底消除地方保护主义；建立健全公众参与与环境行为公示制度；提高环境监管能力建设，切实加大环境执法力度；创新环境执法思路和手段，严打各种环境违法行为等建议。     

论环境的行政公益诉讼

中国尚未建立环境的行政公益诉讼,而传统诉讼制度的问题和缺陷日益显露,导致环境得不到很好地保护。根据环境法中关于环境权的理论、公众参与的原则以及公益诉讼的理论,中国应该尽快建立环境行政公益诉讼制度,赋予公众环境的行政公益诉讼资格,使作为公共利益的环境能得到切实的保护和改善。     

对我国生态补偿的立法构想

分析了以往生态补偿的定义,并从法律的角度给出了生态补偿应有的涵义,即是指为了恢复、维持和增强生态系统的生态功能,国家对导致生态功能减损的自然资源开发或利用者收费(税)以及国家或生态受益者对为改善、维持或增强生态服务功能为目的而作出特别牺牲者给予经济和非经济形式的补偿。回顾了我国有关生态补偿的政策与法律的规定,并探讨了其缺陷:我国有关生态补偿的政策与法律虽然较多,规定得较早,但这些规定很不规范和系统,而且过于原则、缺乏可操作性,对负外部性行为的生态补偿存在政策与法律的缺位,即使是对正外部性行为也并非真正意义上的补偿,而只是一种补助或补贴。对我国生态补偿的立法构建提出了初步设想:一要补偿政策应当法律化,使生态补偿成为一项名副其实的法律制度;二要要构建合理的生态补偿法律体系。     

广州流溪河河岸缓冲带生态治理的优良草种筛选试验

广州流溪河新筑的河堤完全裸露，河流两边的河岸缓冲带受到人类活动的破坏而成为裸露的砂石地或杂草丛生，二者都需要进行生态整治。为了对河流两岸进行生态改造，形成一种护坡效果好、景观效果佳的新流域景观，作者在一段河堤与两块不同性质的河岸缓冲带上进行了适宜草种的筛选试验。在河堤被测试的5个草种中，假俭草的综合表现最好，其次是百喜草，再次是钝叶草与森特钝叶草，野花生的表现最差。在砂石基质的河岸缓冲带样地I，丛生性的大雀稗、弯叶画眉草和香根草表现较好，而匍匐性的野花生、钝叶草和百喜草表现较差，这主要是后三者因根系浅，易遭洪水冲击。至于种植在土质的河岸缓冲带样地Ⅱ上的草种，由于土质状况好，淹水时间短，普遍表现良好。总的来看，弯叶画眉草、大雀稗在河岸缓冲带上的综合表现最好，但如果从耐淹角度来考虑，香根草也应是一个较理想的草种。     

贵州省原煤中微量元素的组成特征

研究了贵州省各主要煤田中主要采煤层的Ａｓ,Ｂ,Ｂａ,Ｂｅ,Ｃｄ,Ｃｏ,Ｃｒ,Ｃ,Ｈｇ,Ｌｉ,Ｎｉ,Ｐｂ,Ｓｂ,Ｓｅ,Ｓｒ,Ｔｌ,Ｖ,Ｚｎ等微量元素的组成特征,贵州省原煤中微量元素的含量总体上的世界范围内的一致,但Ｓｂ,Ａｓ,Ｈｇ等有害元素则明显富集,由于煤炭成因上的特殊性,其微量元素的组成除受煤植物的影响外,后期在煤作用对其有决定性的影响。