HWRC Site Capacity Calculations

A theorectical maximum hourly throughput of vehicles has been calculated per site with consideration of the following:

·  Number of car parking spaces.

·  Proportion of residents spending different amounts of time on site (1-4 mins / 5-9 mins / 10-14 mins / >15 mins), data on which have been collated from site surveys carried out by members of the Waste Management Unit.

Please see the example below for Hoddesdon HWRC:

·  Firstly, the number of visits per hour, in one space, is calculated for each visit length. For example, the number of resident visits in a single space taking 1-4 mins ((60 / 3.5) * 0.31) = 5.3.

·  The number of visits per hour, per space for each visit length is then multiplied by the number of car parking spaces. For example 5.3 * 15 = 80 (rounded).

Hoddesdon / Time Spent On Site - from HWRC Surveys
1 - 4 Mins / 5 - 9 Mins / 10 - 14 Mins / > 15 Mins / INPUTS
Average Time / 2 / 7 / 12 / 17 / Time (mins) / 60
Arrival / Exit / 1.5 / 1.5 / 1.5 / 1.5 / Number of Spaces / 15
Total / 3.5 / 8.5 / 13.5 / 18.5
Resident Split / 31% / 54% / 8% / 7%
Visits by Resident Proportion Split / Visits by Resident Proportion Split / Visits by Resident Proportion Split / Visits by Resident Proportion Split
Single Space / 5.3 / 3.8 / 0.4 / 0.2
For All Spaces / 80 / 57 / 6 / 3
Theoretical Hourly Max. Capacity / 145

Please see the peak and average capacity for each HWRC (excluding Buntingford and Watford) in the table below.

In order to gauge each site’s peak capacity, the peak hourly flow recorded in the trip counter data for February, March, April and May 2011 is divided by the maximum theoretical throughput.

In order to give a better impression of the day to day operation of each HWRC, the average hourly flow recorded in the trip counter data for February, March, April and May 2011 is divided by the maximum theoretical throughput, thus providing a capacity figure for those quieter times at the sites.

Site / Theoretical Hourly Max. Throughput / Peak Recorded Hourly Flow / Site Capacity / Average Hourly Flows / Site Capacity
Hoddesdon / 145 / 73 / 50% / 22 / 15%
Turnford / 134 / 103 / 77% / 51 / 38%
Berkhamsted / 100 / 168 / 169% / 49 / 49%
Hemel Hempstead / 107 / 175 / 163% / 62 / 58%
Bishop's Stortford / 130 / 106 / 82% / 44 / 34%
Ware / 144 / 135 / 94% / 46 / 32%
Elstree / 104 / 76 / 73% / 30 / 29%
Potters Bar / 160 / 120 / 75% / 42 / 26%
Letchworth / 134 / 161 / 121% / 52 / 39%
Royston / 234 / 149 / 64% / 36 / 15%
St. Albans / 115 / 121 / 105% / 46 / 40%
Harpenden / 234 / 118 / 50% / 38 / 16%
Stevenage / 237 / 222 / 94% / 76 / 32%
Rickmansworth / 338 / 125 / 37% / 46 / 13%
Waterdale / 562 / 161 / 29% / 54 / 10%
Cole Green / 80 / 73 / 91% / 34 / 42%

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060711 Waste Management Cabinet Panel Appendix F