Search results for " Curve number"
showing 4 items of 14 documents
EHSM: a conceptual ecohydrological model for daily streamflow simulation
2013
A parsimonious conceptual lumped model is here presented with the aim of simulating daily streamflow in semi-arid areas. The model, processing daily rainfall and reference evapotranspiration at basin scale, reproduces surface and subsurface runoff, soil moisture dynamics, and actual evapotranspiration fluxes. The key elements of this numerical model are the soil bucket, where rainfall, evapotranspiration, and leakage drive soil moisture dynamics, and two linear reservoirs working in parallel with different characteristic response times. The surface reservoir, able to simulate the fast response of the basin, is fed by rain falling on impervious area and by runoff generated with excess of sat…
Standard Asymptotic Response and Expected Runoff from Curve Number Theory
2015
The Standard Asymptotic response is a common finding with rainfall-runoff analysis with the Curve Number method. Widely-observed in data analyses, it is the secondary relationship between the data-defined CN and the causative rainfall P, for which the empirical fitting equation CN(P) = CN∞+ (100-CN∞)exp(-kP) has been found to fit well. This is an unexpected variation in the handbook methodology. It is investigated here on a “theoretical” basis by using the handbook tabled values of CN for the three AMC classes, I, II, and III; the storm-to-storm S (=1000/CN-10); and the observed 12-50-88 percent conditional probabilities for the ARC classes. With this, and treating S as a variable across th…
Estimation of synthetic flood design hydrographs using a distributed rainfall–runoff model coupled with a copula-based single storm rainfall generator
2014
Abstract. In this paper a procedure to derive synthetic flood design hydrographs (SFDH) using a bivariate representation of rainfall forcing (rainfall duration and intensity) via copulas, which describes and models the correlation between two variables independently of the marginal laws involved, coupled with a distributed rainfall–runoff model, is presented. Rainfall–runoff modelling (R–R modelling) for estimating the hydrological response at the outlet of a catchment was performed by using a conceptual fully distributed procedure based on the Soil Conservation Service – Curve Number method as an excess rainfall model and on a distributed unit hydrograph with climatic dependencies for the …
Generation of Natural Runoff Monthly Series at Ungauged Sites Using a Regional Regressive Model
2016
Many hydrologic applications require reliable estimates of runoff in river basins to face the widespread lack of data, both in time and in space. A regional method for the reconstruction of monthly runoff series is here developed and applied to Sicily (Italy). A simple modeling structure is adopted, consisting of a regression-based rainfall–runoff model with four model parameters, calibrated through a two-step procedure. Monthly runoff estimates are based on precipitation, temperature, and exploiting the autocorrelation with runoff at the previous month. Model parameters are assessed by specific regional equations as a function of easily measurable physical and climate basin descriptors. Th…