基于分布式水文模型的嘉陵江流域氮磷非点源污染负荷预测

为研究在大尺度流域上以降雨径流为载体的非点源污染,以基于土地利用的分布式水文模型(SLURP Hydrological model)为基础,提出氮磷负荷预测模型及未来气象参数和土地利用分布图的构建方法.就嘉陵江流域土地利用、畜禽养殖和农业人口未来变化产生的总氮与总磷的月负荷量进行模拟和预测分析.结果表明,预测年降雨径流...     

漓江水资源环境问题的景观生态学思考

漓江风景区是驰名中外的国家级风景名胜区,每年接待国内外游客1 000多万人次,旅游收入达50亿元.但是,近年来随着工农业的快速发展,旅游开发力度的加大,人民生活水平的迅速提高,其生态环境问题日趋严重,主要表现在漓江汛期洪水泛滥、枯水期径流量变小、时间延长,由此引发河流自净能力降低,景区环境污染加重,水质变差,景区美景度和旅游承载力下降.漓江是漓江风景区的核心景观要素,漓江景区的很多生态环境问题均由漓江水资源环境问题引发.该文依据漓江水文观测资料,从景观生态学角度探讨解决其水资源环境问题的对策,为漓江风景区旅游可持续发展寻求新的有效途径.     

Soil erosion and runoff: The need to rethink mitigation strategies for sustainable agricultural landscapes in western Europe

Agricultural landscapes that are intensively farmed, as in western Europe, face the challenge of a transition to more sustainable systems. Although erosion rates are relatively low in western Europe, the agricultural landscape is confronted by the need to mitigate the off-site impacts of erosion. An important challenge is that of disrupting connectivity between runoff and sediment sources, often farmers' fields, and freshwater systems or local communities. Mitigation strategies should include monitoring of erosion rates and off-site impacts and a mix of engineered and alternative measures such as buffer strips and retention ponds. Also needed are supportive government policies and actions including awareness of institutional memory problems and the promotion of farmer education. For the future, the risk of climate change must be appreciated and built into the planning of comprehensive mitigation strategies. Our perspective is that the overall aim should be a ‘sustainable agricultural landscape’ and not simply a reduction of erosion and runoff on farmers' fields.     

Response of hydrological drought to meteorological drought in the eastern Mediterranean Basin of Turkey

The hydrographic eastern Mediterranean Basin of Turkey is a drought sensitive area. The basin is an important agricultural area and it is necessary to determine the extent of extreme regional climatic changes as they occur in this basin. Pearson's correlation coefficient was used to show the correlation between standardized precipitation index(SPI) and standardized streamflow index(SSI) values on different time scales. Data from five meteorological stations and seven stream gauging stations in four sub-basins of the eastern Mediterranean Basin were analyzed over the period from 1967 to 2017. The correlation between SSI and SPI indicated that in response to meteorological drought, hydrological drought experiences a one-year delay then occurs in the following year. This is more evident at all stations from the mid-1990 s. The main factor causing hydrological drought is prolonged low precipitation or the presence of a particularly dry year. Results showed that over a long period(12 months), hydrological drought is longer and more severe in the upper part than the lower part of the sub-basins. According to SPI-12 values, an uninterrupted drought period is observed from 2002–2003 to 2008–2009. Results indicated that among the drought events, moderate drought is the most common on all timescales in all sub-basins during the past 51 years. Long-term dry periods with moderate and severe droughts are observed for up to 10 years or more since the late 1990 s, especially in the upper part of the sub-basins. As precipitation increases in late autumn and early winter, the stream flow also increases and thus the highest and most positive correlation values(0.26–0.54) are found in January. Correlation values(ranging between –0.11 and –0.01) are weaker and negative in summer and autumn due to low rainfall. This is more evident at all stations in September. The relation between hydrological and meteorological droughts is more evident, with the correlation values above 0.50 on longer timescales(12-and 24-months). The results presented in this study allow an understanding of the characteristics of drought events and are instructive for overcoming drought. This will facilitate the development of strategies for the appropriate management of water resources in the eastern Mediterranean Basin, which has a high agricultural potential.     

改进RVA法在河流水文情势评价中的应用

【目的】研究改进变化范围法(Range of Variability Approach,RVA)中各水文指标对生态环境的响应程度,以有效避免RVA在评价河流整体水文情势时容易忽略低度、中度改变指标的不足,为河流生态系统的管理决策提供参考。【方法】基于改进的RVA算法充分考虑了5类33个水文指标与生态系统之间的响应程度,并将层次分析法(主观赋权法)与熵权法(客观赋权法)相结合赋予各指标生态权重,集结并累加各指标综合生态权重与单个水文指标改变度,综合评价河流水文情势的整体改变度。以渭河关中段为例,依据林家村、咸阳、华县水文站1960-2010年的日径流资料,借助Mann-Kendall非参数检验方法诊断径流序列突变点,采用RVA法计算单个水文指标的改变度,利用改进的RVA法对渭河关中段水文情势的整体改变度进行评价。【结果】利用未改进的RVA方法计算得到渭河关中段林家村、咸阳、华县控制断面的整体改变度分别为75%,69%,67%,均属于高度改变;而用改进RVA算法计算得到的林家村、咸阳控制断面的整体改变度分别为51%,40%,属于中度改变,华县控制断面的整体改变度为29%,属于低度改变。对比两种不同评价结果并进行合理性分析可知,基于改进RVA方法的评价结果更加贴近河道所提供的整体信息和指标改变度的分布特征,符合客观实际。【结论】通过赋予各水文指标生态权重,综合考虑各水文指标与生态系统之间的响应程度,能有效融合33个水文指标在评价河流整体改变度时的内涵,研究成果更加客观且符合实际。     

滨海盐碱地白蜡人工林的小气候效应

以滨海盐碱地白蜡人工林为研究对象,以旷野裸地为对照,采用定位观测的方法,研究白蜡人工林的动力、热力和水文等小气候效应,以期为滨海盐碱地人工造林的生态影响评价提供参考.结果表明：林内太阳辐射、风速、土壤温度、土壤湿度明显低于旷野;空气相对湿度林内显著高于旷野;而林内空气温度春季高于旷野,夏秋季则低于旷野.林带防风效应和遮荫效应在夏季发挥最好,分别可达77.87％和67.50％,气温最高可降低0.40℃,空气相对湿度可增加7.59％ ～ 18.61％.林内不同小气候因子间极显著相关,且气温和土温的相关性最好.     

基于土壤相对凋萎湿度构建的干旱监测指标在云南的应用分析

在分析云南土壤水文参数的基础上,构建基于土壤相对凋萎湿度的干旱监测指标I_RWM,并分析其在云南地区的适用性。结果表明：云南0~20 cm土层土壤水文参数空间分布较为一致,土壤水分利用率总体呈现东高西低,南高北低的特点;从I_RWM指标来看,云南轻旱、中旱、重旱和特旱上限对应的土壤相对湿度分别为45.6%、36.5%、27.5%和18.4%;当大部地区土壤相对湿度低于60%时,云南发生中等干旱灾害的可能极大;云南的西部边缘地区对土壤水分更为敏感,有旱情发展波动大的特点;在干旱监测中,I_RWM指标能够降低极端降水对旱情监测的干扰,且对干旱灾害的描述与实际更接近。综合来看,I_RWM指标在云南的适用性优于MCI指数。     

不同植被类型对黄河三角洲贝壳堤土壤水文功能的影响

以滩涂裸地为对照,对黄河三角洲贝壳堤向海侧的盐生灌草、滩脊地带的旱生灌草及向陆侧的盐生草3种植被类型的土壤水文功能进行了研究。结果表明,与裸地相比,贝壳堤生境条件下的盐生灌草、旱生灌草及盐生草3种植被类型土壤容重降低了8.5%~20.8%,总孔隙度增加了17.1%~46.1%。滩脊地带的旱生灌草改善土壤孔隙状况效果最好,向陆侧的盐生草最差。3种植被类型具有一定的压碱抑盐效应,降盐碱功能表现为滩脊地带的旱生灌草最好,其次为向海侧的盐生灌草,而向陆侧盐生草最差。不同被覆地类土壤渗透性能大小表现为:向陆侧盐生草滩脊地带旱生灌草向海侧盐生灌草裸地。0—40cm土层的土壤饱和贮水量和毛管贮水量表现为:滩脊地带旱生灌草向海侧盐生灌草向陆侧盐生草。在垂直层次上,贝壳堤不同植被类型改良盐碱、土壤孔隙状况及贮水性能均表现为0—20cm优于20—40cm土层。研究表明,贝壳堤滩脊地带旱生灌草植被的土壤贮蓄水分及降盐改土能力最优,其次为向海侧的盐生灌草,向陆侧的盐生草较差。     

门头沟西侧小流域地表雨水资源量预测

应用传统的径流系数法与SCS-CN模型法预测了北京市门头沟西侧小流域雨水资源利用潜力,并对比了不同方法预测的雨水资源量及其时空分布规律。结果表明,径流系数法预测的丰水年(P=25%)、平水年(P=50%)、枯水年(P=75%)和多年平均年份地表雨水资源量分别为:2.84×10⁷m³,1.98×10⁷m³,1.22×10⁷m³和2.14×10⁷m³。模型法预测的丰水年、平水年、枯水年和多年平均地表雨水资源量分别为:3.21×10⁷m³,2.16×10⁷m³,1.31×10⁷m³和2.50×10⁷m³,经验法预测值小于模型法。夏季的7月,地表的雨水资源利用潜力达到相应特征年份的最大值。