The relationship between lag time and peak runoff rate can be used to model runoff hydrographs at Nearing et al () provided further support for the role of Almost all of the early work on lag time or time of concentration was concerned. Relation entre écoulement et temps de réponse et effets des états de surface à The relationship between the observed lag time and peak runoff rate was. support. Mr. Robert R. Reynolds, P.E., of KDOT deserves special thanks for his .. The Relationship between Lag Time and Time of Concentration. In flood.
Below is an example of the spread sheet calculations for time of concentration: Curve Number The curve number is the parameter used by the model to estimate the potential maximum retention of rainfall. In other words, with the Curve Number the model determines the amount of excess rainfall that will result in direct runoff. The Curve Number depends on soil type, land use and antecedent moisture conditions.
WMS:Lag Time and Time of Concentration
The land use is urban with a mix of industrial and dense residential development. A value in the range of is a reasonable estimate for the Curve Number.
The length value to use in this equation was difficult to determine. The furthest point from the outlet for this basin is approximately 19, feet. This value of length would not be representative of the length intended for this equation since, judging from the topographic maps and seeing the basin, most of the flow through Northwest Park has traveled a considerable distance in channels.
Therefore I consider a length of approximately feet to be more representative of the basin. Design Storm Design storms are precipitation patterns used for hydrologic modeling. Design storms are based on historical precipitation data for the area of interest.
Lag Time versus Time of Concentration
The design storm used for the input for the model is the alternating block hyetograph. The incremental depth is calculated using discrete time intervals. A design storm of any frequency or duration can be calculated and converted to an alternating block hyetograph. See the sample spreadsheet below. The hyetograph can be shown graphically as follows: The illustration below is a typical HEC1 input file used in my study.
The following parameters were explored: The tables were inserted into Excel where they were rearranged into a useful form for analysis. Design Storms and HEC1 Keeping the Curve Number and the time of concentration constant, 5 different design storms were run in the model.
The following graph illustrates the different resulting outflows for each design storm.
The year storm had the highest peak and volume the area under the curve and the 5 year storm had the lowest. They each had the same duration time. The following hydrographs resulted. The higher curve numbers result in a larger amount of runoff and therefore a higher peak flow and flow volume. The curve number of 93 would be representative of the Shoal Creek watershed because of it being an urban watershed with substantial development.
The curve number of 77 would be representative of a undeveloped watershed with good soil infiltration and slower overland flow velocity. Note how the peak of CN77 is much lower and the curve is flattened out. A smaller lag time smaller time of concentration results in a higher peak flow over a smaller time interval.
WMS:Lag Time and Time of Concentration - XMS Wiki
In a typical protein aggregation kinetic experiment, the time course of protein fibrillation is measured by the absorbance of light at one or more wavelengths using dyes and extrinsic fluorescent probes. The lag phase is of particular interest because it provides critical information about the factors regulating the fibrillation process.
A major challenge is determining which molecular events regulate the lag phase in fibril formation. ThT fluorescence intensity is not an absolute measure of the amount of protein fibrils formed because multiple ThT molecules bind to multiple species, including prefibrillar oligomers and fibrils of differing sizes.
Therefore, the lag time of a ThT assay does not correspond to a particular molecular event and cannot be attributed to primary nucleation events alone. New single-molecule techniques are rapidly emerging.
For example, Horrocks et al. The basic logistic function gives the characteristic sigmoidal shape, but is limited to describing symmetrical progress curves. A geometric representation of these parameters is shown in Fig. Eqn 1 and variations thereof are often used to estimate the empirical parameters for progress curves of protein aggregation experiments. Aggregate concentration is represented as fluorescent intensity percentage of the final aggregates F max.
The curve is typically divided into the lag phase, the growth phase, and the plateau phase. The half-time t 50 is the time at which half of the plateau aggregates are formed.