海绵城市

stormwater runoff and pollutant concentrations in both a traditional development,
 and a development that used low impact development techniques

Increases in total impervious area in each watershed

Regression relationships between total impervious area 
and stormwater runoff/pollutant export

the use of low impact development techniques on a watershed scale can 
greatly reduce the impacts of development on local waterways.

the percentage impervious area is valid as a predictor of 
stream impacts,and it is a simpler indicator to use

a definite relationship appears to exist between
impervious area and multiple measures of stream health

there is a lack of peer-reviewed studies demonstrating the 
effectiveness of the use of LID on a watershed scale

it is more difficult to establish causality when data from 
different watersheds are analyzed at a discreet point in time

compare stormwater runoff volume and pollutant export from adjacent traditional and LID subdivisions, 
as development occurred, and as impervious surfaces were added in each of the watersheds.

location characteristics

the traditonal site

the LId site

objections

objections

The percent impervious of the subdivision

objections

stormwater runoff volume

TP

TN

regression significance testing

TP

TN

this requires many experimental and modeling efforts to test LID characteristics and 
propose an adequate guideline for optimizing LID management.

propose a novel methodology to optimize the sizes of different types of LID

by conducting intensive stormwater monitoring and numerical modeling in a commercial site

1 One of the greatest issues in pollutant emissions is the first flush effect (FFE)

2 Mathematical modeling can be used to determine LID type 
and placement with limited stormwater management funds

3 FFE provides an opportunity for Low Impact Development to be designed 
more effectively by optimizing removal efficiency for the early part of runoff

1 monitor/characterize stormwater runoffs from the study site

2 develop the stormwater model with observations

3 optimize the sizing of different LIDs for mitigating FFE

0.0125 km2

The average annual rainfall 1391 mm

temperatures 29.3
C and -1.9
C

imperviousness approximately 85%

Stormwater runoff

suspended solids

Flow rates

samples for water quality analysis

Model description

LID modules

sensitivity analysis

Model calibration

the module performance

The objective function

The representative rainfall for simulation of optimizing LIDsize

Objective of optimization: MFFn

   the sensitivity analysis by LH-OAT
 hydrological and water quality modules

 ranked the most sensitive parameters 

finds hydrologic and water quality parameters for calibration
using the pattern search tool in MATLAB software

models' performance by the Nash-Sutcliffe

model efficiency coefficients 

 chose 17 h as the value of IETDand estimated 32.4 mm of
average rainfall and an average durationof 8.6 h

SS loadings

the Event Mean Concentrations (EMC)

reduction effect of each LID in terms of SS loadings, EMC, and FFcurves

MFF30 sharply decreased by increasing LID size

 ifMFF30 is equal to 1 for a given LID size,
 we determined it as an optimal LID size. 

this study simulated water quality dynamics using pollutant build-up and a wash-off module,
 coupled with a hydrologic response. （considering FFE rather than whole treatment performance)

This study assessed the performance of rain barrel/
cistern and porous pavement as retrofitting technologies in two urbanized watersheds

Six scenarios consisting of the watershed existing condition,
25% and 50% implementation of rain barrel/cistern and porous pavement,
and 25% rain barrel/cistern combined with 25% porous pavement

a proposed LID modeling framework

the Long-Term Hydrologic Impact Assessment (L-THIA)eLID model.

the application of 50% rain barrel/cistern, 50% porous pavement
and 25% rain barrel/cistern combined with 25% porous pavement
are good retrofitting options in these watersheds. 

simulating watershed level impacts of rain water
 harvesting systems (specifically, rain barrel, cistern)

porous pavement onrunoff,
baseflow, and total streamflow.

 the CurveNumber (CN) method
(the relationship between watershed storage and initial abstraction,)

The relationship between the CN and the watershed storage. S

The model estimates direct runoff (Q, mm)
for a given precipitation depth

an empirical equation，to estimate the baseflow
component of the total streamflow （for the study
region with watershed characteristics）

BFI is the baseflow index. BFI is related to CN
（was developed with data having a CN range of 70-90) 

location

reasons

precipitation data
(The National Climatic Data Center )
weather station 124272 (1991-2010))

 Measured daily streamflow
(the USGS streamflow observation stations
 03353600 and 03353637 (1991-210))

Hydrologic soil group (HSG) information
( the Soil Survey Geographic (SSURGO) database of
the United States Department of Agriculture and
Natural Resources  Conservation using ArcGIS

6 categories of land uses
(National Land Cover Dataset (NLCD)
 with 10 m resolution using ArcGIS)

EMC and BPC values (TN and TP)
(the Indiana Department of Environmental Management
and  Ahiablame (2012) respectively)

 a computational framework

 increasing or decreasing all CN values with a 1% increment at a time (a whole number) using

R2 and NasheSutcliffe efficiency coefficient (NSE) as model performance measures.

Six land use and
planning scenarios (1-6)

the CN values are from literature

Calibration and validation of L-THIAeLID

Performance of LID practices

runoff

baseflow

streamflow

理念

途径

控制指标

技术路线

具体实施

路基下面原土壤层的渗透能力

是否存在易受水和荷载影响的原土层,例如可溶性岩石

存在污染地下水的风险

路基下原土壤层内是否有污染物存在

全渗透

部分渗透 

不渗透

孔隙率

颗粒级配

颗粒形状稳定性

骨料物理特性

抗变形性能

抗腐蚀性能

搭接连接处密封性好

原土壤层（指经施工处理后）的CBR 值

路面上交通量设计值

道路在施工期间的荷载交通量

砂垫层

胶凝粘接粗骨料层

粗骨料层

底基础材料层

结构基础层

一个子流域只有一个水流出口，根据需要将研究区域进行划分

子流域被划分为

节点

连接

融雪

子流域地表的水面

地下水含水层表层

储水单元中的蓄水

融雪

子流域各地表融雪加速趋势不一致造成的

模拟地表以下水分垂直下渗的运动过程

根据降水量估算流入或下渗到下水道系统中的水量。

作为子流域的固有属性

直接入流

晴天入流

降水-入流和下渗RDII

调控准则

模拟用户自定义的任意数量的污染物的产生、流动和运移过程

根据土地利用的分类

冲刷和累计函数

给节点赋予一组处理函数

流入项

流出项

霍顿方程

格林安普特方程

径流曲线数值方法

对于一定孔隙率phi的土层来说，含水量是一定的

其含水量theta经常发生变化

稳定流法

运动波法

动力波法