SIMPLE DESIGN FOR SIMULTANEOUS STEADY-STATE INFILTRATION EXPERIMENTS WITH RING INFILTROMETERS1

ABSTRACT: A successful procedure for measuring steady-state infiltration rates at remote locations is described. The equipment for the simultaneous experiments is of simple design, inexpensive, and rugged. A total of 247 steady-state infiltration measurements were made across a small rangeland catchment using the procedure as described. The reason for the measurements was to characterize the spatial variability of infiltration across the catchment. The limiting factor for the multiple-ring system as employed in this study was a sufficient water supply to conduct the experiments to completion.     

BEST MANAGEMENT PRACTICES FOR STORM WATER AND INFILTRATION CONTROL1

ABSTRACT: Water quality controls of storm water runoff and infiltration should be a major part of a nonpoint source control program. Although surface runoff and ground water controls are often approached separately, coordination between the two is essential. For practical reasons, a rather simplified technology-based approach appears to be desirable. Areas affected vary greatly as to their sensitivity to pollution; and the various classes of pollutant source vary greatly as to their potential harmfulness. In effect, a matrix approach appears best, in which both vulnerability of the area and harmfulness of the pollutant source would have weight in determining which level of best management practices (BMP) would be appropriate, whether standard, special, or complete prohibition of the type facility under given circumstances.     

APPLICATION OF INFILTRATION THEORY FOR THE DETERMINATION OF EXCESS RAINFALL HYETOGRAPH1

ABSTRACT: The purpose of this paper is to show through the use of numerical examples that modern infiltration theory can be used in everyday hydrologic practice. The actual use of four methods of calculation of infiltration rates and of excess rainfall rates is demonstrated for the case when simultaneous data of rainfall and stream flow are available for a watershed. The four methods are: (1) the well known Π-index method, (2) the traditional Horton's infiltration capacity formula, (3) the less traditional Green and Ampt infiltration capacity formula, and (4) a ponding time approach. It is recommended that hydrologists become at least familiar with the numerical procedures involved in the ponding time and postponding infiltration approach. This approach, though not flawless, should be preferred to the other three methods if use of the other three is at all considered.     

土壤毛管渗滤系统在浙江湖州某区新农村示范工程中的应用

针对浙江湖州某区生活污水的特点，分析了国内外生活污水处理的各种常规工艺，以采用先进的土壤毛管渗滤处理技术为主，结合能耗很低的微动力生化预处理和人工生态塘处理技术，取得了良好的处理效果。并详细介绍了土壤毛管渗滤处理系统的组成、各个处理单元的设计参数，分析总结了设计工艺的特点。     

降雨入渗与地表径流污染减量模拟试验研究

针对造成水体污染的城市降雨地表径流问题,建立模拟降雨系统,选用聚合物与功能材料,改良土壤结构,提高土壤对雨水的渗透性,削减地表径流及径流携带污染物对纳污水体的污染.结果表明,复合施用PAM与沸石使降雨径流过流体土壤结构被改良,对降雨径流的削减作用明显,对土壤的降水渗透有显著的促进.数据表明,沸石与PAM配施对削减降雨地表径流与提高降雨土壤入渗的效果有协同作用.在36、72和108 mm/h不同降雨强度下,处理土壤水的入渗较对照分别提高了35%～76%、32%～66%和18%～47%,降雨后土壤的含水量较对照可提高1～5倍.     

人工快渗的强化预处理研究

通过室内实验并结合实际工程研究了一种新型组合式人工快渗系统处理氨氮负荷较高的污水。结果表明,简易曝气装置有效降低了人工快渗池的污染物负荷,保障了整个系统的出水水质。实际工程中,经过简易曝气池的预处理,人工快渗池的水力负荷可达2.5 m/d,降低了人工快渗系统的占地面积,出水COD、氨氮、总氮等指标达到了《城镇污水处理厂污染物排放标准》(GB/T18918-2002)一级A排放标准。     

SPATIAL VARIABILITY OF CONDUCTWITY AS APPLIED TO DISTRIBUTED PARAMETER INFILTRATION MODELS1

ABSTRACT: Two infiltration models, called VVSIM (variable variance stochastic infiltration model) and EVVSIM (enhanced variable variance stochastic infiltration model), are developed in this study. A distributed parameter infiltration model can estimate the amount of infiltration over a field area by computing the infiltration over zones of the field area. Hydraulic conductivity is the most important parameter determining infiltration in simulations by infiltration models. The performance of an infiltration model depends on how well the model accommodates the complicated spatial distribution of hydraulic conductivity. The two proposed models include the effects of spatial correlation of the conductivity distribution. Virtual conductivity fields are generated using the turning bands method. Monte Carlo simulations show that the proposed models give infiltration estimates more accurate than those obtained by the other models employed.     

高家坪隧道岩溶水系统识别及涌水量预测

为查明在建宜保高速高家坪隧道内ZK45+995m处突水点的补给来源以及隧道区的水文地质条件,并预测可能的涌水量,在对隧道区内岩溶发育规律调查分析的基础上,先后在隧道区开展了两次地下水示踪试验,结果查明:高家坪隧道内ZK45+995m处突水点的补给来源于隧道北侧的下埫岩溶洼地,汇水面积为0.66km2,突水点所处的岩溶管道为黄龙洞岩溶水系统的西支,为单一岩溶管道类型,地下水最大流速为341 m/d,平均流速为244m/d,地下水流速快,管道介质相当发育。根据示踪试验划分的黄龙洞岩溶水系统与干洞坪岩溶水系统边界范围,并利用黄龙洞泉长期降雨量-泉流量监测数据,采用大气降雨入渗法预测高家坪隧道ZK45+995m处突水点未来可能遭遇的最大涌水量为13 216m3/d,正常涌水量为5 940m3/d,为隧道防治水方案的制定提供了水文地质依据。     

水稻田非点源污染原位试验研究

为了研究野外水稻田的非点源污染,本试验采取一种新的原位观测方法:即在不改变水稻田原有出流特征前提下,在水稻生长季采集田面水水位和降雨信息,通过水位变化曲线计算水稻田每日的蒸散发和渗漏损失量,再根据水量平衡关系计算径流量.观测期间定期采集田面水测定总氮(TN)、总磷(TP)浓度,根据径流量和浓度估算非点源污染流出负荷量.试验选取北京市海淀区上庄镇某村水稻田试验田块,通过1年的试验观测得到在生长季内的37场降雨中共有9场降雨产生了出流.另外,还有2次人工排水和1次农田回归流形成了非点源污染.经计算试验区水稻田每个生长季TN输出系数为8.8 kg·hm-2,TP输出系数为0.47 kg·hm-2.该观测方法针对具有多出水口且最低田埂高度动态变化的野外水稻田的非点源污染观测具有较强的可操作性.     

熔渗温度和时间对 C/C-SiC-ZrC 复合材料性能的影响研究

目的研究熔渗温度和熔渗时间对复合材料密度和弯曲性能的影响。方法采用化学气相渗透法(CVI)和聚合物浸渍裂解法(PIP)制备熔渗用低密度C/C复合材料,以Si0.9-Zr0.1合金为熔渗金属,采用反应熔渗法(RMI)制备C/C-SiC-ZrC复合材料。测试C/C-SiC-ZrC复合材料的开孔率、密度、弯曲强度,分析试样的相组成。结果熔渗温度为1450℃时,复合材料的密度仅有1.97 g/cm3,弯曲强度仅为153 MPa;当熔渗温度升高到1550℃时,密度和弯曲强度分别升高到2.39 g/cm~3和260 MPa;而当熔渗温度升高到1650℃时,密度和弯曲强度又分别降为2.18 g/cm~3和208 MPa。1.5 h熔渗时复合材料的密度值最大,为2.46 g/cm~3,相对0.5 h熔渗的最小值提高了5.1%;1.0 h熔渗时复合材料材料的弯曲强度最高,达到了260 MPa,相对于1.5 h熔渗的最低值仅提高了3.2%。结论复合材料的致密度和弯曲强度随熔渗温度的升高先升高后降低,密度随熔渗时间的延长而增大,而弯曲强度随熔渗时间的延长先升高后降低,但密度和弯曲强度随熔渗时间的延长变化较小。