Inflow through and around MH lids

Hello.

Is anyone aware of what typical inflow rates through pickholes and
around the circumference of submerged MH lids are? All I am able to
locate is a technical document produced by and available for download at
the "neenah foundry" web site. Also, if anyone is aware of the
existence of literature regarding this subject, I'd appreciate it if you
would post their references. Thank you.

Chris Kresin
chris@KRESINENGINEERING.CA

ASCE M&R No. 62 (WPCF MoP FD-6) "Existing Sewer Evaluation and
Rehabilitation" has some information on inflow, from an undated report
by Neenah Foundry Co. Check Page 26 and Table 2.1. Tests were done
under three conditions: splashing, 3 mm head, and 25 mm head over
maintenance hole cover. Two cover types were tested: non-machined
bearing surface, and machined bearing surface. Average inflows (gallons
per minute) were:

Test 1 Test 2 Test 3
Non-machined 3.99 10.63 16.80
Machined 1.06 1.81 2.54

A table footnote provides inflow rates for each test:
Test 1. 0.25 gpm/sq in
Test 2. 1.00 gpm/sq in
Test 3. 4.94 gpm/sq in

gpm x 5.45 = m^3/day

Neil Jordan
NJordan@EXPONENT.COM