Streambank sediment loading rates at the watershed scale and the benefit of riparian protection

Streambank erosion is a pathway for sediment and nutrient loading to streams, but insufficient data exist on the magnitude of this source. Riparian protection can significantly decrease streambank erosion in some locations, but estimates of actual sediment load reductions are limited. The objective of this research was to quantify watershed‐scale streambank erosion and estimate the benefits of riparian protection. The research focused on Spavinaw Creek within the Eucha‐Spavinaw watershed in eastern Oklahoma, where composite streambanks consist of a small cohesive topsoil layer underlain by non‐cohesive gravel. Fine sediment erosion from 2003 to 2013 was derived using aerial photography and processed in ArcMap to quantify eroded area. ArcMap was also utilized in determining the bank retreat rate at various locations in relation to the riparian vegetation buffer width. Box and whisker plots clearly showed that sites with riparian vegetation had on average three times less bank retreat than unprotected banks, statistically significant based on non‐parametric t‐tests. The total soil mass eroded from 2003 to 2013 was estimated at 7.27 × 10⁷ kg yr.^?1, and the average bank retreat was 2.5 m yr.^?1. Many current erosion models assume that fluvial erosion is the dominant stream erosion process. Bank retreat was positively correlated with stream discharge and/or stream power, but with considerable variability, suggesting that mass wasting plays an important role in streambank erosion within this watershed. Finally, watershed monitoring programs commonly characterize erosion at only a few sites and may scale results to the entire watershed. Selection of random sites and scaling to the watershed scale greatly underestimated the actual erosion and loading rates. Copyright © 2016 John Wiley & Sons, Ltd.     

新疆新源县暴雨洪涝灾害风险区划

本研究选用新疆新源县34个气象站2010-2019年日降水量、地理信息及社会经济等数据,采用归一化及GIS等方法,结合致灾因子危险性、孕灾环境敏感性和承灾体易损性,得出新源县暴雨洪涝灾害5个等级风险区划图。结果表明：新疆新源县暴雨洪涝灾害风险呈“东-北”分布的趋势,吐尔根乡、吐尔根农场、阿热勒托别镇、坎苏乡与那拉提镇属于洪涝高风险区;阿热勒托别镇、坎苏乡与那拉提镇的大部分区域及71、72团场属于次高风险区;新疆新源县中东部区域为中等风险区;其余区域为次低风险区与低风险区。     

晋祠泉域岩溶水生态系统健康评价

文章尝试性地提出岩溶水生态系统的概念,从系统的特征、功能和面临的威胁三方面论述了其内涵,基于驱动力-压力-状态-影响-响应(DPSIR)模型,综合考虑自然因素和人类活动叠加影响,构建了岩溶水生态系统健康评价指标体系;用层次分析法(AHP)确定指标权重,用综合评价法确定岩溶水生态系统所处健康状态,并将其分为很健康、健康、亚健康、不健康和病态五级。并以晋祠泉域为例,采用ArcGIS空间分析技术确定岩溶水生态系统健康评价等级。结果表明:泉域煤矿开采区处于不健康状态,东部平原区和中部径流区均处于亚健康状态,碳酸盐岩裸露区和汾河周边区域处于健康状态,分别占晋祠泉域总面积的29%、31%和40%。     

ArcGIS下的油田勘探资料管理方案

在长期的石油勘探工作中积累了包括地震、测井、地质以及其它非震地球物理方法等方面的大量资料。对这些与空间信息密切相关的资料进行数字化管理的理想方案是通过地理信息系统平台实现。油气勘探数据管理系统选用ArcGIS平台。用商业DBMS如oracle8作为数据库服务器，采用三层式C／S结构，用ESRI的Geodatabase模型和ArcSDE建立分布式勘探地理数据库。整个勘探地理数据库按专业或专题分为若干子库，每个子库都可以位于地理位置不同的专业数据服务器上，通过油田内部宽带网连接。制订勘探资料元数据标准，并根据元数据标准编制元数据同步程序和编辑器，实现油田勘探资料的规范化管理。     

地形图自动分幅模型的设计与实现

地形图分幅空间数据库常规构建方法对操作者要求较高,步骤烦琐,效率较低.本文基于ArcGIS Model Builder设计了一套地形图自动分幅模型,实现了自动构建适应研究区范围的多种比例尺地形图分幅空间数据库的功能.该模型可以很好地实现共享与复用,减少重复性劳动,提高数据处理效率,具有较好的推广意义.文中对模型设计流程...     

徐州煤矿地质资料数据库建设及应用

通过对徐州煤矿地质资料的标准化整理，归纳并探讨多源数据融合的原则和标准，形成统一的空间坐标参数和数据格式，达到多源数据统一融合的目的。基于ArcGIS平台，建立涵盖基础地质、矿山开发利用、钻孔、采空区、塌陷及已治理区5大专题的煤矿地质资料数据库。项目成果纳入徐州自然资源“一张图”系统中，服务于矿政管理、矿地融合研究、工程建设新项目规划选址、国土空间规划等工作。     

基于ArcGIS的网格化雷电灾害风险评估方法研究与应用*

结合镇海区实际，开展大片区建（构）筑物网格化雷电灾害风险评估模型构建与应用，解决雷电灾害风险评估仅停留在依据灾后损失指标的单体建（构）筑物风险分布评估情况。在常规电气—几何雷电灾害风险评估模型基础上创新应用，引入地理信息处理技术将评估区域进行网格化分割，建立格点内包含建（构）筑物高度及其梯度、土壤电阻率及其梯度、直击雷防护效率、有效截收面积、地闪密度、电子电气设备系统、人口密度、火灾风险等指标在内的多层次网格化雷电灾害风险评估模型，并以辖区某化工企业厂区雷电灾害风险评估为例，对模型实践可行性应用示例。结果表明：对各指标数据集综合分析计算并运用ArcGIS风险区划，结合厂区功能布局特点分析评价，结果与市级雷电灾害风险评估报告、省级雷电易发区划基本一致。采用地理信息技术网格化处理大范围、跨区域雷电灾害风险评估方法，从“点”到“面”建立数学模型，对评估区域范围及扩展范围的雷电灾害风险评估、风险区划、政府决策支持等具有指导意义。