First flush pollution load of urban stormwater runoff

Abstract

In a storm event, a first flush (FF) phenomenon occurs when most of the pollution load is transported in the initial part of the event discharged volume. The objectives of the study were to consider its severity for a number of pollutants as well as to recognize rainfall–runoff characteristics that influence it. The study was conducted in a semi-arid region of a mixed residential and commercial urban catchment in Iran. Ten major rainfall events were monitored for total solids (TS), total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), Zn, and Pb. Total suspended solids and COD were usually above the permitted discharge. Power and polynomial functions fit well to the normalized curve of the distribution of pollutant load with volume. Discharge loads of TN, Pb, and Zn were approximately uniform. There was a relatively weak FF for TS, TSS, and COD. No correlation between FF load of TS and COD and rainfall–runoff characteristics was observed, but the amount of the FF load of TSS increases when the intensity and duration of a rainfall event increase. Key words: first flush, urban runoff quality, pollution load distribution, event mean concentration, urban stormwater runoff.

The temporal changes in road stormwater runoff quality and the implications to first flush control in Chongqing, China

“…As shown in Table 4, the FF 30 values of TP, TSS, and DCu were significantly positively related to rainfall, average rainfall intensity, and maximum rainfall intensity (p<0.05), which are similar to previous studies (Deletic 1998;Taebi and Droste 2004;Luo et al 2012). However, the FF 30 values for all the parameters studied were not correlated with the time of maximum rainfall intensity, which differs from the previous study.…”

“…Han et al (2006) reported that 30 to 35 % of the mass was contained in the first 20 % of the runoff. Deletic (1998) and Taebi and Droste (2004) concluded that the magnitude of FF is positively and significantly correlated to the maximum rainfall intensity.…”

Stormwater Runoff Characteristics and Effective Management of Nonpoint Source Pollutants from a Highland Agricultural Region in the Lake Soyang Watershed

“…In Naedongcheon (the upper part of the Mandae area) and Jungjohangcheon (the upper part of the Jaun area), the first flush is indicated by the SS, TP and BOD values. Although the first flush mostly occurs during storm events in highly paved watersheds in urban and mixed land use areas [14,17,23], the first flush phenomenon was identified in the agricultural region of this study, where excessive soil erosion occurs. The shape of the M(V) curve of the rainfall event occurring on 1-3 October in Jungjohangcheon is concave (Figure 6) because the rainfall intensity was high at the final stage of rainfall.…”

Characteristics of Rainfall Runoff Pollutant and Initial Treatment

“…In addition to this, Deletic, 1998 andTaebi et al (2004) conducted research into early-stage storm water and reported that early-stage storm water phenomena are complicated and vary greatly according to regional characteristics [15,16]. According to Taebi et al (2004), it was reported that as the urbanized area and impervious area ratio were higher, the first flush effects were greater [16]. It is expected that in the case of runoff water reduced by filtration facilities, treating the overflows of early-stage rainfall when pollutant loads are relatively higher is the preferred method of maximizing the reduction of pollutant loads.…”

“…Sansalone et al (1997) defined it to be early stage storm water if the standard cumulative pollutant loads exceed the standard cumulative runoff curve [14]. In addition to this, Deletic, 1998 andTaebi et al (2004) conducted research into early-stage storm water and reported that early-stage storm water phenomena are complicated and vary greatly according to regional characteristics [15,16]. According to Taebi et al (2004), it was reported that as the urbanized area and impervious area ratio were higher, the first flush effects were greater [16].…”