Porirua Stream at Town Centre
Daily maximum flow and suspended sediment concentration (SSC) for the 2018/19 monitoring season. SSC is predicted using a turbidity vs discrete SSC model that is updated annually, see last year’s report for more information. The flow event lines represent the flow level at which we would expect n years before another event that size.
Event Loads
Event
|
Duration
|
Sediment load (t)
|
Sediment yield (t/ha)
|
Max flow (m3/s)
|
Flow return period (years)
|
08-07-2018 - 09-07-2018
|
1 day, 11 hrs & 45 mins
|
1184
|
0.30
|
39.6
|
2
|
21-07-2018 - 22-07-2018
|
0 days, 6 hrs & 55 mins
|
73
|
0.02
|
19.0
|
1
|
12-10-2018 - 12-10-2018
|
0 days, 10 hrs & 20 mins
|
149
|
0.04
|
16.2
|
1
|
19-12-2018 - 20-12-2018
|
1 day, 14 hrs & 55 mins
|
257
|
0.07
|
24.5
|
1
|
08-03-2019 - 08-03-2019
|
0 days, 10 hrs & 30 mins
|
127
|
0.03
|
15.3
|
1
|
06-04-2019 - 07-04-2019
|
1 day, 18 hrs & 40 mins
|
132
|
0.03
|
15.9
|
1
|
11-04-2019 - 12-04-2019
|
1 day, 13 hrs & 40 mins
|
471
|
0.12
|
31.7
|
1
|
Annual Loads
Year
|
Time
|
Sediment load (t)
|
Sediment yield (t/ha/yr)
|
2012
|
124 days 12 hrs
|
327
|
0.08
|
2013
|
365 days
|
2,554
|
0.65
|
2014
|
365 days
|
1,303
|
0.33
|
2015
|
365 days
|
7,699
|
1.96
|
2016
|
366 days
|
7,383
|
1.88
|
2017
|
365 days
|
4,069
|
1.03
|
2018
|
365 days
|
3,342
|
0.85
|
2019
|
180 days
|
1,063
|
0.27
|
Total
|
2,495 days 12 hrs
|
27,739
|
7.05
|