基于专家-层次分析法的地质灾害风险性评价——以广西富川瑶族自治县为例

本文利用专家-层次分析法对地质灾害风险性进行评价,以广西贺州市富川瑶族自治县地质灾害风险调查评价为依托,通过资料分析和现场调研,根据各类地质灾害构建其风险性评价指标体系,采用专家-层次分析法对地质灾害风险性进行研究,研究结果表明:将富川瑶族自治县地质灾害风险分区分为高、中、低3种类型,富川瑶族自治县面积为1572.5 km²,其中地质灾害高风险区(I)的面积约为166.37 km²,约占研究区面积的10.58%;地质灾害中风险区(II)的面积为167.37 km²,约占研究区面积的10.64%;地质灾害低风险区(III)的面积约为1238.76 km²,约占研究区面积的78.78%。借助GIS平台实现可视化,评价结果对广西地区地质灾害的防治具有指导意义。     

四川旺苍县化龙乡土地质量及生态农业建设

为研究四川省旺苍县化龙乡土地质量,通过对449件土壤样品测试分析。结果显示:研究区土壤养分TFe₂O₃丰富(一等),Zn、Cu、MgO、K较为丰富(二等),P、CaO、Se较为缺乏,Ge、Mo缺乏,局部具富Ge土壤。综合养分以三等土壤为主,面积为25.96 km²,占81.13%；二等土壤面积为3.69 km²,占11.52%,四等土壤面积2.35 km²,占7.37%。土壤质量综合评价一等优质土壤面积为0.02 km²；二等良好土壤面积为0.44 km²；三等中等土壤面积为17.84 km²；四等差等土壤面积为13.64 km²；五等劣等土壤面积为0.08 km²。龙乡优质(一级)土地可适于发展有机、绿色食品。良好(二级)土地可适于发展无公害食品。中等(三级)土地种植较为安全。较差(四级)土地可适当发展林业。劣等(五级)土地可改造成建筑用地。为生态农业建设、振兴乡村经济提供技术支撑。     

粤港澳大湾区惠州市地质环境安全综合评价

地质环境安全评价是一项关于国土空间规划的基础性工作,其目的是对人类生命财产、城镇和工程建设构成威胁的地质环境问题进行评价。惠州市为粤港澳大湾区东部中心城市,经济总量位居广东省第五,为粤港澳大湾区经济增量最快最大的城市。开展惠州地区地质环境安全评价,对城市建设和生态系统的发展有着极为重大的意义。本文选择惠州市惠城区惠南湖片区进行综合地质评价,通过实地野外调查采样分析,查明该区内地层岩石、地质构造等特征以及地下水类型、地质灾害发育情况和水土环境质量与污染状况,在此基础上进行综合评价,并将研究区按工程建设及国土空间开发适宜性进行分区,其中适宜区面积2.43 km²,占比40.50%;基本适宜区面积0.69 km²,占比11.50%;适宜性差区面积2.18 km²,占比为36.33%;不适宜区面积0.69 km²,占比11.50%。研究成果可为惠州城市整体规划、工程建设与开发利用等提供基础性地质资料和科学建议。     

罗布泊盐湖罗北凹地矿区卤水数值模拟研究

罗北凹地钾盐矿区自开采以来地下卤水位持续下降,呈负均衡。目前的钾盐资源现状是资源储量难以长期满足当前钾肥生产规模的需求,对未来钾肥生产的可持续发展构成严重的隐患,进而威胁国家粮食安全。本文以罗北凹地钾盐矿区为研究区,通过建立基于GMS的地下卤水数值模型及预报模型,获得未来3年和5年地下卤水位变化动态及降深值。结果表明,与现状条件相比,研究区潜水水流方向总体上和初始流场形态基本一致,而承压水在开采井附近流场形态发生较大变化,出现明显的降落漏斗。经3年开采后,研究区潜水总体降深2~4 m左右,其中个别开采区中心的最大降深可达到6 m以上。降深面积分布较为广泛,开采区降深2 m以上区域面积达376.77 km²;开采5年后降深2 m以上区域面积达 718.60 km²。研究区承压水总体降深0~4 m左右,其中个别开采区中心的最大降深可达到10 m以上。降深面积分布较为广泛,开采区降深4 m以上区域面积达194.11 km²。而开采5年后降深4 m以上区域面积达338.00 km²。模拟结果可为矿区卤水资源管理和优化开采提供依据。     

基于县域尺度城镇建设适宜性评价——以晋中市太谷县为例

城镇建设适宜性评价是国土空间规划的重要基础,也是资源环境承载能力和国土开发适宜性评价的重要内容。本研究以“双评价”技术指南为指导,构建了县域尺度的城镇建设适宜性评价技术,在土地资源评价、水资源评价、气候评价、环境评价、地质灾害评价和区位优势度评价的基础上,开展太谷县城镇建设适宜性评价,划分适宜、一般适宜和不适宜3类区域。结果表明,太谷县城镇建设适宜区面积为278.84 km²,占比26.68%;一般适宜区面积为185.90 km²,占比17.79%;不适宜区面积为580.27 km²,占比55.53%。受地形地貌的影响,城镇建设适宜性评价结果具有典型的区域特征,适宜区和一般适宜区主要分布于晋中盆地区域内,不适宜区主要分布于东部山区。受活动断层影响,适宜区内发育地裂缝地质灾害,且分布有北东向条带状的不适宜区,在国土空间开发利用时需要注重地质灾害的防范。     

基于信息量法的重庆云阳县(三峡库区)地质灾害易发性评价

云阳县地处重庆市东部,属三峡库区,构造上位于川东弧形构造带东北段,褶皱形态以宽平的屉形向斜和狭窄的高背斜相间排列,组成隔挡式构造。区内地貌以中-高山峡谷地貌为主,第四纪以来一直处于间歇性抬升状态,地形切割强烈,长江河道从境内穿过,河流水系发育,年降雨量大,地质环境条件脆弱,地质灾害发育。论文基于Arcgis平台,运用信息量法全面分析了影响云阳县地质灾害发育的地形条件、地层岩性、地质构造、河流水系、人类工程活动等因素,建立了云阳县地质灾害易发评价指标体系。评价结果表明,高易发区面积576 km²,占比15.8％,中易发区面积1801.68 km²,占比49.41％；评价结果可为云阳县区域地质灾害防治提供依据,也可为三峡库区地质灾害易发性评价提供参考。     

龙口市浅层地温能潜力评价及经济环境效益分析

浅层地温能作为绿色新能源,近年来在越来越多的地区得到开发与应用,通过对龙口市主城区展开水文地质调查、地温场调查、现场热响应试验及热物性试验等工作,查明了工作区浅层地温能的赋存条件,得到了地埋管型地源热泵的开发利用潜力分区,并通过等效计算获得浅层地温能开发利用经济、环境效益价值。根据调查与计算分析可知:考虑土地利用系数时,(1)工作区地下水换热系统夏季可制冷面积1082.00×10⁴ m²,冬季可供暖688.55×10⁴ m²;地埋管换热系统夏季可制冷面积1573.43×10⁴ m²,冬季可供暖1677.81×10⁴ m²。(2)浅层地温能开发利用总能量为755.79×10⁴ GJ/a,折合标准煤15.06×10⁴ t/a,节煤量43.04×10⁴ t/a,热资源价值10543.51万元/a。(3)可减少排放氮氧化物、二氧化硫、二氧化碳、悬浮质粉尘、生成煤灰碴等总计37.91×10⁴ t/a,节省污染治理费4249.03万元/a。     

甲基丙烯酸酯类用于基岩固结灌浆试验研究

能否用有机化合物作基岩的固结灌浆材料,是我们研究化学灌浆的出发点之一。本文叙述了用甲基丙烯酸酯类化学灌浆材料,对一坝址石英闪长岩的弱风化带进行团结灌浆试验,通过试验所测得的岩石变形模量由26.3×10⁴kg/cm²提高到47.4×10⁴kg/cm²,静力弹性模量由29.6×10⁴kg/cm²提高到57.9×10⁴kg/cm²,声波速度Vp由4894m/s提高到5272m/s,单位吸水率ω由0.0351/（min·m·m）降低到0.0121/（min·m·m）,缝面的粘结强度由零提高到13.4kg/cm²。     

城市湖泊湿地对空气PM_(10)、PM_(2.5)的影响——以武汉为例

选择武汉城市三环内主城区8块湖泊湿地为研究对象,采用小尺度定量测定的方法,研究城市湖泊湿地对空气PM_(10)、PM_(2.5)的影响。测定时间为2014年7月上旬7∶00—19∶00,每1h一次分别对8块湖泊湿地及对照处的PM_(10)、PM_(2.5)进行同步测定,挑选晴好无风相似的3d进行数据分析。结果表明:1)城市湖泊湿地与对照处的PM_(10)、PM_(2.5)差值变化与湖泊湿地面积、位置、形状、环境类型指数均呈正相关,其中湖泊湿地面积、位置指数的贡献值最大。2)随着城市湖泊湿地面积的增大,增湿效应逐渐加强,降低空气PM_(10)、PM_(2.5)效应呈现了一定的增强趋势,其中对空气PM10浓度的影响更为显著,当湖泊湿地面积为12.2hm2时,湖泊湿地与周边对照处的冷暖空气流动作用明显,空气中携带的粉尘颗粒物容易向湿度较低的方向扩散,从而改善湿地空气质量。当湖泊湿地面积达到临界值之后,多斑块离散型湖泊湿地布局对整个城市环境的空气质量改善效应更为显著。     

延庆地区水头村泥石流形成条件及发展趋势

水头村泥石流沟是延庆地区典型沟谷型泥石流沟之一,具易发性高、危险性大的特点,严重威胁下游水头村村民。本文以水头村泥石流沟为研究对象,通过精细调查与GIS统计分析,获取了该流域降雨、地形地貌、物质来源等信息,对泥石流流域分区特征和形成条件进行研究,综合14个识别因子,确定了该泥石流沟的发展阶段,并预测其发展趋势,通过单沟泥石流堆积区公式预测了该流域最大危险区,并提出了防治措施建议。研究表明：水头村泥石流沟内松散堆积物动储量达27.96万 m³,其中以残坡积和冲洪积为主要物源;该泥石流属于暴雨-沟谷型-支沟群发型泥石流沟,发展阶段处于形成期,最大危险区面积为0.737 km²,威胁沟口水头村住户21户59人和红水公路350 m。建议采用定期巡视+局部物源稳固+清理排导槽相结合的防治措施。研究成果可为该区泥石流灾害防治提供基础数据支撑和科学依据。     

近30年太湖流域湿地生态系统服务价值 对景观格局变化的响应：基于“退田还湖” 工程的实施

由于太湖流域湿地生态系统服务价值(ESV)受到"退田还湖"工程实施的影响,定量研究其发展演变规律,能够为流域湿地的保护提供参考。运用RS和GIS技术,以1990、2000、2010和2019年TM遥感影像为数据源,对4个时期太湖流域湿地景观格局动态变化进行研究,并分析"退田还湖"工程实施前后湿地ESV变化规律,探讨工程对湿地生态效益的影响。研究表明:1)1990—2000年,在"围湖造田"工程的影响下,太湖流域湿地总面积减少了3010.35km~2,其中自然湿地减少了4554.01km~2,湿地ESV降低了35.73%;2)2000—2010年,在"退田还湖"工程实施初期,自然湿地的减少趋势得到控制,湿地ESV提高了77.96%,湿地斑块数目(NP)增加了126%,香农多样性指数(SHDI)呈上升趋势;3)2010—2019年,在"退田还湖"工程的推进下,湖泊湿地呈增长趋势,坑塘与水库面积显著增加,受湿地总面积减少的影响,湿地ESV下降;4)总体来看,1990—2019年太湖流域湿地面积减少了29.40%,湿地ESV减少了50.07%。"退田还湖"工程实施前后,太湖流域湿地ESV对湿地...     

Decline of wetland ecosystems in the coastal plain of Israel during the 20th century: Implications for wetland conservation and management

Severe competition for water and augmented agricultural and urban development in Israel have modified and destroyed wetland habitats. Using historical maps, we mapped the past extent of swamps and natural rain pools along the central coastal plain of Israel and compared this with the present extent as reflected in reports, field surveys and satellite images. Out of 192 swamps and rain pools recorded in historical sources, only 18% (35) still exist today. Extrapolation from 69 new records of rain pools (missing in historical sources), suggests that in the 19th century, before many of the wetlands were drained, transformed to agricultural land, or built over, the number of wetland habitats in the coastal plain was threefold higher. In addition to reduction of wetland number, human activity has also diminished wetland size. In rainy winters wetland areas in the coastal plain in the past were an order of magnitude larger than they are today (27.6 and 2.4 km², respectively). At present, the existing natural water bodies along the coastal plain are temporary, small, and surrounded by built-up areas and roads. The grave state of the wetlands in Israel underscores the urgent need for protection of the remnant wetland sites. Following the successful example of wetland restoration in the Hula Valley, we recommend restoring various historical wetlands that have been drained.     

Evaluating mangroves of Krishna Wildlife Sanctuary in relation to the general status of mangroves in Andhra Pradesh,India

The present study was carried out to check whether there is a decline in mangrove cover of Andhra Pradesh state, India, as cited by a few studies. The research analysed mangrove dynamics of Krishna Wildlife Sanctuary of Andhra Pradesh state, using temporal satellite data of six periods. Analysis of these data showed major changes in the mangrove areas of the sanctuary. In 1972, the mangrove cover was 82.76 km², which then decreased to 80.47 km² in 1981, and then further dropped to 69.52 km² in 1990. Comparatively an area of 13.22 km² was lost from 1972 to 1990. The area recorded in 2000 was 101.98 km² and the positive trend of increase in mangrove areas was observed in both 2009 (138.36 km²) and in 2014 (158.16 km²). Overall, an increase of 88.64 km² mangrove area was observed from 1990 to 2014. The study confirms the increase in mangrove cover in the state, disagreeing with the observations of decrease in mangrove cover made by other studies previously.     

Photochemistry of excited-state species in natural waters: A role for particulate organic matter

Laser flash photolysis (LFP) was used to characterize a triplet excited state species isolated from Black River and San Joaquin wetlands particulate organic matter (POM). The solubilized organic matter, isolated from POM by pH-independent diffusion in distilled water, was named PdOM. UV–visible absorption spectroscopy, excitation–emission matrix spectroscopy (EEMs), and ¹H NMR were used to characterize the PdOM. While LFP of dissolved organic matter (DOM) is known to generate the solvated electron, LFP of the PdOM transient in argon-, air-, and nitrous oxide-saturated solutions indicated that this was a triplet excited state species (³PdOM*). The lifetime and the reactivity of ³PdOM* with sorbic acid, a triplet state quencher, were compared with that of the triplet excited state of benzophenone, a DOM proxy. A second excited state species (designated DOM*), with a longer lifetime, was reported in a number of previous studies but not characterized. The lifetime of DOM*, measured for seventeen organic matter isolates, lignin, tannic acid, and three wetlands plant extracts, was shown to differentiate allochthonous from autochthonous DOM. ³POM* and DOM* were also observed in lake water and a constructed wetlands' water. Aqueous extracts of fresh and aged plant material from the same wetland were shown to be one source of these excited state species. This study provides evidence of a role for POM in the photochemistry of natural and constructed wetland waters.     

Organic matter accumulation during maturation of gravel-bed constructed wetlands treating farm dairy wastewaters

The accumulation of organic matter (OM) was investigated after two and five years in a series of four gravel-bed constructed wetlands supplied with different hydraulic loading rates (21, 26, 46 and 72 mm d⁻¹) of farm dairy wastewaters. At these hydraulic loadings, mean wastewater loadings of particulate OM (determined as volatile suspended solids) to the wetlands ranged between ∼1.7 and 5.8 g m⁻² d⁻¹. Vertical and horizontal gradients of OM accumulation, measured by “loss on ignition”, were sampled by stratified coring at 18 sites in each wetland, and their impact on wastewater residence times investigated in three of the wetlands using bromide as a conservative tracer. Mean accumulations of OM in the wetlands after five years operation ranged between 6.8 and 14.9 kg m⁻², increasing with wastewater loading rate. The annual rates of accumulation during the first two years were 1.2 to 2-fold higher than those in the subsequent three years. Around 50–60% of the OM occurred within the gravel substratum, the remainder forming surface sludges, commonly exceeding 50 mm depth over much of the wetland substratum. OM accumulation in the wetlands considerably exceeded that contributed from applied wastewaters, with wetland plant derived detritus supplying substantial additional quantities of OM. The effective void space of the wetland substrata was markedly reduced in the highest loaded wetland, with mean wastewater retention time reduced to ∼50% of its theoretical value (corrected for evapotranspiration losses). In contrast, the lowest-loaded wetland exhibited retention times close to theoretical values. There was, however, no direct relationship between OM accumulation and the effective retention times of the wetlands, suggesting other factors, such as differences in OM bulk density, spatial patterns of accumulation and plant root growth, and inorganic accumulations, were also influencing their hydrology.     

Ecological issues related to wetland preservation, restoration, creation and assessment

A wide range of local, state, federal, and private programs are available to support the national (USA) policy of wetland ‘No Net Loss’. Implementation of programs, however, has resulted in the continued loss of natural wetlands on the premise that restored or created wetlands will replace the functions and values lost by destruction of natural wetlands. What are the ecological implications and consequences of these programs from a biodiversity and ecosystem perspective? From a biodiversity perspective, ongoing wetland protection policies may not be working because restored or created wetlands are often very different from natural wetlands. Wetland protection policies may also be inadequate to preserve and restore ecological processes such as nutrient cycling because they mostly focus on individual wetlands and ignore the fact that wetlands are integral parts of landscapes. Wetland mitigation projects, for example, often result in the exchange of one type of wetland for another and result in a loss of wetland functions at the landscape level. The most striking weakness in the current national wetlands policy is the lack of protection for ‘dry-end’ wetlands that are often the focus of debate for what is and what is not a wetland. From an ecological perspective, dry-end wetlands such as isolated seasonal wetlands and riparian wetlands associated with first order streams may be the most important landscape elements. They often support a high biodiversity and they are impacted by human activities more than other types of wetlands. The failings of current wetland protection and mitigation policies are also due, in part, to the lack of ecologically sound wetland assessment methods for guiding decision making processes. The ecologically based Hydrogeomorphic (HGM) approach to wetland assessment has the potential to be an effective tool in managing biodiversity and wetland ecosystem function in support of the national ‘No Net Loss’ policy.     

Nutrient release from integrated constructed wetlands sediment receiving farmyard run‐off and domestic wastewater

Constructed wetland sediments are frequently contaminated with nitrogen and phosphorus. There is a risk that accumulated pollutants can either be remobilised or reach the groundwater. Five identical mesocosms, which were filled with subsoil collected from full‐scale integrated constructed wetland (the first cell receives the most contaminated influent), were set up to examine nutrient removal within sediment layers. The results indicated that accumulated nutrients leached out into inflow water and that the sediment capacity of nutrient retention decreased as the wetlands aged. Furthermore, the mesocosm planted with Phragmites australis achieved better treatment results compared with the one planted with Agrostis stolonifera. The risk of contamination to groundwater does not exist because none of the treated water reached the bottom outlet during the study period. Both the bentonite (clay) and biogeochemical processes taking place within sediments proved to be efficient in preventing polluted water from infiltrating into lower lying soils.     

Agricultural pesticides threaten the ecological integrity of northern prairie wetlands.

The northern Great Plains of North America has millions of small wetlands, and these are often dispersed through cultivated fields. We investigated relationship between pesticide occurrence and precipitation in selected wetlands in a 30.4 x 10(4) km2 area of the Great Plains with relatively uniform farming practices and 1,777,600 wetlands (southern Saskatchewan, Canada). By early July after pesticides have been applied to crops, the mean number of pesticides detected in wetlands ranged from 1.8 in regions with little precipitation (< 21 mm rain during the previous 15 days) to 3.2 in regions under higher rainfall (> 90 mm). The proportion of wetlands in which at least one pesticide exceeded Canadian guidelines for the protection of aquatic life increased from 0% to 60% over this same precipitation range. The maximum number of pesticides detected in a single wetland was six. Concentration of lindane in wetlands increased with increasing precipitation. Using geographic information on rainfall, wetland densities, area seeded to crops, and region specific relationships between pesticides and precipitation, we estimated the number of wetlands in Saskatchewan with elevated levels of pesticides. In early July, during 3 of the 6 years, the number of wetlands subjected to pesticide levels that exceeded guidelines for the protection of aquatic life was significant, ranging from 152,000 to 424,000 wetlands or 9-24%, respectively, of the total. Lindane and triallate exceeded the guidelines most frequently.