
Xing FangAuburn University | AU · Department of Civil Engineering
Xing Fang
Ph.D., P.E., BC.WRE, F.EWRI, F.ASCE
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205
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September 1995 - August 2007
August 2007 - present
Publications
Publications (205)
Based on Section438 of the Energy Independence and Security Act of 2007, the U.S. Environmental Protection Agency (USEPA) published a report providing technical guidance that recommends using the 95th percentile rainfall event for federal development or redevelopment projects to preserve or restore predevelopment hydrology of the site. In this stud...
Hydrologic design of water management infrastructures is based on specific design storms derived from historic rainfall events available in the form of intensity-duration-frequency (IDF) curves. However, it is expected that the frequency and magnitude of future extreme rainfalls will change due to increase in greenhouse gas concentrations in earth'...
Linear construction typically uses drainage conveyances to convey stormwater runoff away from construction sites to neighboring water bodies. These conveyances may be unstablilized and highly susceptible to erosive shear stresses associated with high-velocity flow. In certain situations, wattle ditch checks are used to help reduce channel erosion c...
Results of a lake model intercomparison study conducted within the framework of Lake Model Intercomparison Project are presented. The investigated lake was Großer Kossenblatter See (Germany) as a representative of shallow, (2 m mean depth) turbid midlatitude lakes. Meteorological measurements, including turbulent fluxes and water temperature, were...
The rational method for peak discharge (Qp) estimation was introduced in the 1880s. The runoff coefficient (C) is a key parameter for the rational method that has an implicit meaning of rate proportionality, and the C has been declared a function of the annual return period by various researchers. Rate-based runoff coefficients as a function of the...
The U.S. Environmental Protection Agency (USEPA) published technical guidance to help federal agencies in implementing Section 438 of the Energy Independence and Security Act of 2007, which requires federal development or redevelopment projects to preserve or restore predevelopment hydrology of the site. The technical guidance recommends retaining...
The runoff coefficient, C, of the rational method is an expression of rate proportionality between rainfall intensity and peak discharge. Values of C were derived for 80 developed and undeveloped watersheds in Texas using two distinct methods. First, the rate-based runoff coefficient, C rate , was estimated for each of about 1,500 rainfall-runoff e...
Cisco (Coregonus artedi Lesueur) was projected to persist in at least 171 deep, clear lakes in a climate-warmed Minnesota, U.S.A. A process-oriented, dynamic, one-dimensional yearround lake water quality model was used to predict coldwater habitat as a function of Secchi depth (a surrogate of lake productivity) and geometry ratio = As0.25/Hmax (a m...
“Eutrophication” is originally used to describe aging process whereby a lake is transformed from a lake to a marsh to a meadow (fill the lake with sediments). “Cultural eutrophication” occurs when the lake aging process is quickened or accelerated by excess nutrients from human activities [1]. Understanding of the fate and transport of water qualit...
Please read/download the final version in GMD, 2013, DOI:10.5194/gmd-6-1337-2013
Results of a lake model intercomparison study conducted within the framework of Lake Model Intercomparison Project are presented. The investigated lake was Großer Kossenblatter See (Germany) as a representative of shallow (2 m mean depth) midlatitude turbid lakes. Met...
The cisco Coregonus artedi is the most common coldwater stenothermal fish in Minnesota lakes. To project its chances of survival under future warmer climate conditions, an oxythermal habitat variable, i.e., the water temperature at 3 mg/L of dissolved oxygen in stratified lakes (TDO3) was calculated from simulated daily temperature and DO profiles...
A deterministic, process-oriented, dynamic and one-dimensional year-round lake water quality model, MINLAKE2010, was developed for water temperature (T) and dissolved oxygen (DO) simulations to study impacts of climate warming on lake water quality and cisco fish habitat. The DO model is able to simulate metalimnetic oxygen maxima in vertical DO pr...
The conventional point-source discharge permitting approach, referred to as the National Pollutant Discharge Elimination System (NPDES), is based on either a regulatory low flow (hydrologic, biological, or seasonal) criterion or on a hydrograph controlled release (HCR) approach. Regulatory low flows are often estimated using empirical equations bec...
Accurate calculation of conjugate depths in a hydraulic jump is important to hydraulic design in open channels. Iterative formulae for calculating conjugate depths in hydraulic jumps in trapezoidal open channels were developed using mathematical transformation of the momentum equation. Two formulae that are adjusted from the critical depth of trape...
The time of concentration (T c) is an important parameter for hydrologic design, analysis, and modeling. Error in the estimation of T c will cause error in prediction of peak discharge (Q p), resulting in an incorrect design. Overland flow T c depends on several factors, such as rainfall intensity (i), length (L), topographic slope (S 0), and flow...
Gravity currents (GC) caused by saline water propagating into freshwater bodies is an interesting phenomenon in environmental fluid mechanics that has received attention from several past investigations. Numerical modeling tools have been proposed in such investigations to predict the advance, mixing and spreading of these currents. While modeling...
In this study, a watershed model WARMF (Watershed Analysis Risk Management Framework) was applied to the Saugahatchee Creek Watershed in Alabama to investigate hydrologic and water quality response to historical land use scenarios and potential future climate change scenarios. Based on monthly average of daily predicted values, land use changes fro...
Ditch checks are used throughout highway construction and are a critical element in the erosion and sediment control plan. The purpose of a ditch check is to reduce flow rates, thereby minimizing channel erosion. Proper installation is required for these devices to perform as intended. Auburn University's Erosion and Sediment Control Testing Facili...
Engineers design a substantial fraction portion of infrastructure that accommodates storm water drainage and conveyance. Estimation models of the response for a watershed typically contain some form of watershed slope as a principal parameter, and the response is usually inversely proportional to that slope. Therefore, as topographic slope decrease...
Fish habitat in lakes is strongly constrained by water temperature (T) and available dissolved oxygen (DO). With climate warming both of these water quality parameters will change. A fish habitat simulation model was developed to calculate an oxythermal habitat variable, TDO3, i.e. water temperature at 3 mg/L of DO, from simulated daily T and DO pr...
The rational method for peak discharge (Q(p)) estimation was introduced in the 1880s. Although the rational method is considered simplistic, it remains an effective method for estimating peak discharge for small watersheds. The runoff coefficient (C) is a key parameter for the rational method and can be estimated in various ways. Literature-based C...
The USEPA as well as state environmental agencies have established strict effluent limitations emphasizing a need for reducing the amount of sediment-laden stormwater runoff discharging into local waterways and watersheds from active construction sites. Therefore, highway construction sites require effective erosion and sediment control practices f...
Water quality and fish habitat models were developed and applied to investigate impacts of future climate change in aquatic systems, mainly lakes in this study. Long-term daily water temperature and dissolved oxygen (DO) profiles and ice/snow covers on lakes were simulated for 27 types of small lakes (surface area up to 10 km2) at 209 geographic lo...
Correlation analysis and a water productivity indicator are used to investigate the inverse relationship between increasing grain output and declining irrigation water use in Hebei Province, People's Republic of China, especially since 2003. A rapid improvement in water productivity more than offset the decline in available water even in one of the...
The rational method was originally developed to estimate peak discharges for sizing drainage structures, such as storm drains and culverts. The modified rational method (MRM) is an extension of the rational method to produce simple runoff hydrographs. The MRM is often called the rational hydrograph method. Application of the MRM produces a runoff h...
Climate warming would alter water temperature and dissolved oxygen (DO) characteristics of lakes. These changes can be expected to have an effect on fish populations. A process-oriented, dynamic, one-dimensional year-round lake water quality model was developed and applied to simulate daily temperature and DO profiles in Minnesota lakes over 48 (19...
This note presents iterative formulas that can be used to calculate the normal depth for all types of horseshoe cross sections. Based on the principle of gradual optimization fitting, general estimation formulas were developed for direct computation of the normal depth for all types of the standard horseshoe cross sections. The estimation formulas...
This technical note presents general equations for the geometric elements of all types of horseshoe cross-sections used in water conveyance systems such as for irrigation, drainage, and water supply projects. We derived iterative formulas for calculating critical depth of general horseshoe cross-sections, and these formulas can be used for computer...
Global climate change and cyclical droughts threaten water supplies in many cities in the United States and across the world. At the same time, rapid population growth has occurred in many urban regions, bringing additional demand for adequate quantity and quality of drinking water. Development of more watersupply reservoirs is a long-term solution...
The rational method introduced in 1880s is often considered simplistic and still frequently used for estimating peak discharges for small drainage areas. The runoff coefficient (C) is a key parameter for the rational method, and typical C values are given and listed in various design manuals and textbooks for different land use conditions. Actually...
Under the challenges of present and future population increase, urbanization, and global climate change, hydraulic analysis and design for water supply, drainage, and irrigation conveyance system are becoming increasingly important in order to solve the water management problem. Determination of critical and normal depths for irrigation and drainag...
It is widely recognized that land development, especially in urban areas, is responsible for significant changes in hydrological runoff characteristics. Stormwater detention is one of the most popular methods that are used in stormwater management and required for urban land development by many local management authorities. The stormwater detention...
The state-of-the-art in one-dimensional lake modelling is briefly reviewed and the motivation for a Lake Model Intercomparison Project (LakeMIP) is presented. The objectives, methodology and implementation phases of the LakeMIP are outlined. Some results from the first intercomparison study are presented. The lake models used in the study range fro...
This paper describes the objectives and shows some preliminary results obtained throughout the first phase of the Lake Model Intercomparison Project, termed LakeMIP. Parallel to this poster, an oral presentation will focus in turn on other features of the project. This international effort started off after the workshop “Parameterization of Lakes i...
The Lake Model Intercomparison Project (LakeMIP) is an international project initiated by participants of the
workshop “Parameterization of Lakes in Numerical Weather Prediction and ClimateModelling” held in September 2008 in St. Petersburg (Zelenogorsk), Russia. LakeMIP offers an opportunity for a comprehensive evaluation and validation of many la...
The geometry of highway pavement and drainage inlets, especially cross slope, longitudinal slope, and local depression and transition length, usually determine the highway surface drainage capacity. In this study, a three-dimensional computational fluid dynamics (CFD) software, FLOW-3D, is used to develop models simulating unsteady, free-surface, s...
National Point Source Discharge Elimination System (NPDES) permits, by state environmental regulatory agencies, are used to control point source pollution in a watershed. Controlling point source pollution through NPDES permitting has resulted in significant improvements in stream and lake water quality. Most often these permits require point sourc...
Modeling studies examining the effect of lakes on regional and global climate, as well as studies on the influence of climate variability and change on aquatic ecosystems, are surveyed. Fully coupled atmosphere-land surface-lake climate models that could be used for both of these types of study simultaneously do not presently exist, though there ar...
Daily water temperature, dissolved oxygen (DO) profiles, and ice and snow covers (where applicable) were simulated for 27 types of small lakes (up to 10 km 2 surface area) at 209 locations in the contiguous United States under past climate (observed from 1961 to 1979) and for projected doubled atmospheric carbon dioxide (2×CO 2) climate conditions....
Global climate change and its related impacts on water supply are universally recognized. In the past few years, drought impacts affecting big metropolitan water supplies alone have plagued Maryland and the Chesapeake Bay in 2001 through 2002, Lake Mead in Las Vegas in 2000 through 2004, the Peace River and Lake Okeechobee in South Florida in 2006,...
Unsteady free-surface flow in open channels with or without in-channel structures are very complex. It is a difficult and challenging subject for civil engineering students to fully understand and comprehend. In this study three-dimensional numerical simulations were performed for several case studies of open channel flows and used to demonstrate s...
Proper highway drainage is essential to ensure safe and comfortable conditions for the road users. The highway pavement and inlet geometry, especially cross slope and longitudinal slope and local depression and transition length, usually determine the highway surface drainage capacity. In this study, FLOW-3D is utilized to model the unsteady free-s...
The time of concentration T c for a watershed is a widely used time parameter to estimate peak discharges in hydrologic designs. In this study, T c is estimated for 96 Texas watersheds using five empirical equations: Williams, Kirpich, Johnstone–Cross, Haktanir–Sezen, and Simas–Hawkins methods. The drainage areas of watersheds studied are approxima...
Characterization of hydrologic processes of a watershed requires estimation of the specific time-response characteristics of the watershed. In the absence of observations these characteristics are estimated from watershed physical characteristics. An exploratory assessment of a particle-tracking approach for parametrizing unit hydrographs from topo...
Time of concentration T c is the time required for runoff to travel from the hydraulically most distant point to the outlet of a watershed. The Natural Resources Conservation Service NRCS velocity method commonly is used to estimate T c for hydrologic analysis and design. The NRCS velocity method applies the physical concept that travel time is a f...
Texas Department of Transportation (TxDOT) hydraulic engineers use a variety of hydrologic technologies to produce peak discharge estimates that are then used to size storm drainage facilities. One of those technologies is the unit hydrograph method. The principal unit hydrograph method used by TxDOT analysts is the Natural Resources Conservation S...
The unit hydrograph is a well-documented method for predicting the runoff hydrograph of a watershed given an excess rainfall hyetograph. Watershed-specific unit hydrographs are parameterized by some conceptual time such as time to peak runoff or time of concentration. Estimation of time parameters when paired rainfall and runoff observations are av...
Data from over 1,600 storms at 91 stations in Texas are analyzed to evaluate an instantaneous unit hydrograph IUH model for rainfall-runoff models. The model is fit to observed data using two different merit functions: a sum of squared errors function, and an absolute error at the peak discharge time Q p MAX function. The model is compared to two o...
Flash flooding is the rapid flooding of low lying areas caused by the stormwater of intense rainfall associated with thunderstorms. Flash flooding occurs in many urban areas with relatively flat terrain and can result in severe property damage as well as the loss of lives. In this paper, an integrated one-dimensional (1-D) and two-dimensional (2-D)...
Time of concentration (Tc) is an important parameter for hydrologic design. An underestimate of Tc typically leads to an overestimate of peak discharge for the design. In this study, Tc is estimated for 92 Texas watersheds using three different methods: the NRCS (Natural Resources Conservation Service) velocity method, rainfall-runoff hydrograph an...
The statistical relation between main channel length (MCL) and basin length (BLENG) was investigated for 96 small watersheds in central Texas. MCL and BLENG were calculated using 10- and 30-meter digital elevation models (DEM). Because of a possible curvilinear relation between MCL and BLENG for watersheds with
BLENG greater than about 16 kilometer...
The design of small runoff-control structures, from simple floodwater-detention basins to sophisticated best-management practices, requires the statistical characterization of rainfall as a basis for cost-effective, risk-mitigated, hydrologic engineering design. The U.S. Geological Survey, in cooperation with the Texas Department of Transportation,...
An open channel flow is a flow having a free surface subject to atmospheric pressure. Open channel design is to design a channel to carry a certain amount of flow from one location to another under any provided channel geometry and topographic conditions. Parameters to define channel geometry include channel shape, cross-sectional area, wetted peri...
Streamflow is an important component of the hydrologic cycle. Streamflow typically quantifies as volumetric discharge in cubic meter or feet per second. Streamflow, at a given location on a stream, is usually represented by a hydrograph. A streamflow hydrograph is a graphical representation of instantaneous discharge at a given location with respec...
A review of the literature addressing sediment transport in gravel-bed river systems and structures designed to control bed-load mobility is provided as part of Texas Department of Transportation research project 0-4695: Guidance for Design in Areas of Extreme Bed-Load Mobility. The study area comprises the western half of the Edwards Plateau in ce...
The Natural Resources Conservation Service (NRCS or formally SCS) dimensionless hydrograph (DH) procedure was derived from a large number of natural unit hydrographs from watersheds varying widely in size and geographical locations. This DH has been widely used for many hydrological design practices. This DH has two key parameters: time to peak and...
The unit hydrograph is defined as a direct runoff hydrograph resulting from a unit pulse of excess rainfall generated uniformly over the watershed at a constant rate for an effective duration. The unit hydrograph method is a well-known hydrologic-engineering technique for estimation of the runoff hydrograph given an excess rainfall hyetograph. Four...
The purpose of this study is to use sediment settling data to analyze and predict performance of 15 Confined Placement Areas (CPAs) as part of the 50 year dredged material management plan. Two modules of the Automated Dredging and Disposal Alternatives Management System (ADDAMS), DYECON and SETTLE, were used to design CPAs. Design variables for CPA...
Fish habitat is strongly constrained by water temperature and dissolved oxygen. Thermal/dissolved oxygen habitat for warm-water fish in small lakes was therefore determined from simulated daily water temperature and dissolved oxygen profiles. Twenty-seven types of lakes were simulated with past (1961-1979) climate conditions observed at 209 weather...
Fish habitat is strongly constrained by water temperature and available dissolved oxygen (DO). Thermal/dissolved oxygen habitat for cold-water fish in small lakes was therefore determined from simulated daily water temperature and dissolved oxygen profiles. Twenty-seven types of lakes were simulated with past (1961-1979) climate conditions observed...
Fish habitat is strongly constrained by water temperature and available dissolved oxygen (DO). Thermal/DO habitat for cool-water fish in small lakes was therefore determined from simulated daily water temperature and DO profiles. Twenty-seven types of lakes were simulated with past (1961–1979) climate conditions observed at 209 weather stations in...
A database of incremental cumulative-rainfall values for storms that occurred in small urban and rural watersheds in north and south central Texas during the period from 1959 to 1986 was used to develop empirical, dimensionless, cumulative-rainfall hyetographs. Storm-quartile classifications were determined from the cumulative-rainfall values, whic...
Hyetographs and storm depth distributions are important elements of hydraulic design by Texas Department of Transportation engineers. Design hyetographs are used in conjunction with unit hydrographs to obtain peak discharge and hydrograph shape for hydraulic design. Storm-depth distributions can be used to assess the probability of a total rainfall...
In the early 2000s, the Texas Department of Transportation funded several research projects to examine the unit hydrograph and rainfall hyetograph techniques for hydrologic design in Texas for the estimation of design flows for stormwater drainage systems. A research consortium comprised of Lamar University, Texas Tech University, the University of...