Exploring the future impacts of urbanization and climate change on groundwater in Arusha,Tanzania

ABSTRACT

We combine satellite imagery, urban growth modelling, groundwater modelling and hydrogeological field expeditions to estimate the potential impacts in 2050 of rapid urbanization and climate change on groundwater in Arusha, Tanzania, and by extension similar areas in Sub-Saharan Africa. Our analysis suggests that a reduction of groundwater recharge by 30–44% will cause groundwater levels to drop by up to 75 m, mainly due to increased evapotranspiration and to an expansion in paved surface. If this scenario becomes reality, we predict that wells will run dry, creating health, social and environmental risks.     

基于小波分析的丹江口水库水文年度入库径流变化特征

根据丹江口水库运行调度的实践,采用Morlet小波函数,对丹江口水库水文年度、汛期和非汛期的径流时间序列进行小波分析,揭示了丹江口水库入库径流多时间尺度的复杂结构,并分析了不同尺度下径流序列的周期变化和突变点。研究结果表明：水文年度、汛期、非汛期入库径流序列都存在9,20,40,50a的主要周期,并且水文年度入库径流与汛期径流具有相似的周期演变特征。研究成果可供丹江口水库运行调度参考。     

Achieving the Sustainable Development Goals: improving water services in cities affected by extreme weather events

Abstract

This article discusses how key risks from extreme weather events might affect progress towards meeting Sustainable Development Goals 6 and 11 in cities in developing countries. It outlines the magnitude of the existing shortfall in safe water and sanitation services, and how climate change will exacerbate existing problems. It argues that the performance of many governments thus far has lacked urgency and purpose. Unless governments in particular become more committed, with redoubled effort, the goals are unlikely to be achieved.     

贵州省1960-2014年降水量时空变化特征分析

基于贵州省1960-2014年19个气象站点的降水观测数据,采用一元线性回归拟合、累计距平、MannKendall突变检验等方法,分析贵州省55年的年、最大月降水量的时空变化规律。结果表明:贵州省1960-2014年年均降水量总体呈南多北少的空间分布格局,以-17. 815 mm/10a的变化率在逐年减少,自20世纪80年代以来变化尤其不稳定;岩溶槽谷降水量的增加趋势明显,而岩溶盆地下降趋势明显,岩溶峡谷、岩溶槽谷和非喀斯特区在近几年来的降水量较不稳定;贵州省降水受地形地貌和季风的影响显著,逐年明显的极端气候对农作物的生长和社会经济发展存在不利影响。研究结果对贵州省短期气候预测、制定旱涝灾害预警机制和合理利用水资源等具有重要意义。     

尼尔基水库枯季径流预报方法分析

利用尼尔基水库52 a径流资料,分析了前后期径流（流量）相关法在尼尔基水库枯季径流预报中的适用情况,认为10月31日平均流量与11月至次年3月的径流量相关性较好,可用于尼尔基水库枯水期径流预报。     

Tributary confluences are dynamic thermal refuges for a juvenile salmonid in a warming river network

As rivers warm, cold‐water fish species may alleviate thermal stress by moving into localized thermal refuges such as cold‐water plumes created by cool tributary inflows. We quantified use of two tributary confluence plumes by juvenile steelhead, Oncorhynchus mykiss, throughout the summer, including how trout positioned themselves in relation to temperature within confluence plumes. At two confluences, Cedar and Elder creeks, along the South Fork Eel River, California, USA, we monitored temperatures using in situ logger grids throughout summer 2016. Fish were counted within confluences via snorkel surveys five times a day on 5 days at each site. We found diel and seasonal dependence on confluence use by steelhead, especially at the Cedar Creek confluence, where mainstem temperatures exceeded 28°C. At this site, fish moved into the confluence on the warmest days and warmest times of the day. Fish observed within the Cedar Creek confluence plume were most common in locations between 20–22°C, rather than the coldest locations (14.5°C). At Elder Creek, where mainstem temperatures remained below 24°C, there was little relationship between mainstem temperature and steelhead presence in the confluence plume. At both sites, steelhead distribution within plumes was influenced by spatial variation of temperature and mean temperature in surveyed grid cells. Our results show that cool tributaries flowing into warmer mainstem reaches (over 24°C) likely create important thermal refuges for juvenile steelhead. As mainstem rivers warm with climate change, cool‐water tributary inputs may become more important for sustaining cold‐water salmonids near the southern end of their range.     

常州市湖塘纺织工业园降雨径流污染负荷分析

我国当前以实现分流制为规划指导原则,分流制下工业园区雨水径流污染对水环境存在较大潜在影响。在此背景下采用SWMM软件模拟降雨和实地调研相结合的方法,分析湖塘园区降雨径流的污染负荷。结果表明:0.25年一遇的降雨径流质量浓度峰值ρ(TN)=6.01 mg/L,ρ(TP)=0.02 mg/L,ρ(COD)=125.21 mg/L,该降雨重现期下的TN和COD浓度均远劣于GB 3838—2002《地表水环境质量标准》的Ⅴ类水标准;随着降雨重现期增大,径流污染物浓度峰值会进一步提高。排入受纳水体采菱港的污染物总量比例:径流中TN占园区总TN(径流+点源)排放量的25.9%,径流中TP占4.4%,COD占28.0%,COD、TN径流污染量占整个园区污染总量的比重较大。结合湖塘园区排水系统的实地调研,建议加强园区初期雨水截留、推广园区中水回用和推进园区与企业排口设置规范化,以有效降低园区雨水径流对周边水环境的影响。     

乌兹别克斯坦水资源变化及其对供给压力的影响

梳理文献资料,结合农业、遥感和气象水文产品数据,分析乌兹别克斯坦水资源变化及水资源供给压力。分析表明:自1980年以来,乌兹别克斯坦年平均取水量由59亿m~3增至102亿m~3,灌溉农业消耗了90%以上的水资源;尽管1992年以来耕地面积总体呈下降态势(200km~2/a),且高耗水作物种植比重下降(-3.24%),但受气候变暖的影响(0.31℃/(10a)),单位面积作物需水量持续增加(3.27mm/a),导致总的需水量仍呈增加态势(2.75亿m~3/a);与此同时,上游来水量减少以及上游国家用水的增加,将进一步加剧区域水资源短缺及供给压力。为应对水资源问题,乌兹别克斯坦需加强水管理,改进灌溉技术,提高用水效率,同时,需寻求完善跨境河流水资源分配与管理的途径。该研究有助于增进对乌兹别克斯坦水资源问题的认识,并为应对该问题提供科学依据,以及为"一带一路"合作发展提供支撑。     

黄土高塬沟壑区水土保持对小流域地表径流的影响

水土保持对径流的作用是水土流失治理中一个亟待回答的实际问题．本文用小流域平行对比观测法，分析了黄土高塬沟壑区水土保持对小流域地表径流的数量及其时间分布特征的影响，表明在黄土高塬沟壑区，水土保持能使小流域产洪次数减少、地表径流模数和径流系数减小；使小流域地表径流模数的年际变率增大；在洪水产流过程中，水土保持使流域产流起始时间滞后，径流持续时间缩短，瞬时流量及洪峰流量降低以至消失     

海河流域径流演变规律及其对气候变化的响应

根据海河流域长系列水文气象资料,对流域内年径流量的演变趋势、突变特征和周期性规律进行分析,同时选取降水量和气温这两项重要的气候要素,建立海河流域年径流与降水、春夏气温的统计回归模型,计算未来A1B、A2和B1三种气候条件下的径流量,从而分析径流量对气候变化的响应。