This function calculates the time in minutes that is needed for the water to travel through the affected urban river stretch for a yearly rain event, based on a natural catchment discharge
Usage
get_HQ_time_interval(
area_catch,
river_cross_section,
river_length,
river_mean_flow,
Hq_pnat1_catch = NULL,
slope = 0.1
)Arguments
- area_catch
The catchment area in km2
- river_cross_section
The average river cross section in the catchment in m2
- river_length
The length of the affected urban river stretch in m
- river_mean_flow
The Average river flow in m3/s
- Hq_pnat1_catch
the natural catchment discharge for a yearly rain event in L/(s*km2). If NULL it will be estimated by slope and area of the catchment
- slope
Average slope of the catchment in % (Default is 0.1)
Details
The natural catchment discharge is estimated based on the supplementary information of DWA-A 102-3. Unlike the rain intensity of a yearly rain, the estimated natural discharge is independent of the rain duration. According to DWA-A 102-3 two more factors would increase the travel time that are not considered here: 1) The longest travel time within the sewer network of the planning area and 2) The increased water level leading to a higher river cross section and thus to a longer travel time. Instead a constant of 60 minutes is added to the calculated travel time. This also ensures that the rain duration is high enough (> 60 min) for a toxicological relevance.