equations
From Water Supply and Sewerage by Terence J. McGhee, McGraw-Hill, Sixth Ed.
1. Population projection models
P0, P1, P2 = three successive census populations
Pt = future population
Psat = saturation population
Dt, n = period of projection, time interval
K, K1, K2, a, b = constants
Arithmetic method (equation 2.3 in McGhee): 
Uniform percentage model (equation 2.5 in McGhee): 
Logistic model (equation 2.6 in McGhee): 
where:
(equation 2.7 in McGhee): 
(equation 2.8 in McGhee): 
(equation 2.9 in McGhee): 
Declining growth method (equation 2.12 in McGhee): 
2. Variations in water use
Goodrich formula (equation 2.13 in McGhee): 
where: p = % of annual average rate and t = period in days.
Fire flow (equation 2.14 in McGhee): 
where F = flow in USG/min, A = total floor area in sq.ft., and C is a fire coefficient.
3. Basic fluid mechanics
Bernoulli's equation (equation 3.1 in McGhee): 
Reynold's number (equation 3.2 in McGhee): 
Darcy-Weisbach equation (equation 3.3 in McGhee): 
Thickness of laminar sub-layer (equation 3.6 in McGhee): 
Hazen-Williams equation (equation 3.8 in McGhee): 
Head losses in fittings (equation 3.12 in McGhee): 
Head loss in abrubt expansions (Borda-Carnot loss, equation 3.13 in McGhee): 
Head loss in gradual enlargements (central angle exceeding 45 deg, equation 3.14 in
McGhee): 
Chezy equation (equation 3.26 in McGhee): 
Manning's equation (3.34 in McGhee): 
Ditto, another form (equation 3.35 in McGhee): 
Specific energy (equation 3.36 in McGhee): 
Critical depth for a wide, rectangular section (equation 3.38 in McGhee): 
Critcal velocity, ditto (equation 3.40 in McGhee): 
Critical flow for non-rectangular sections (equation 3.41 in McGhee): 
Sharp-crested suppressed rectangular weir (equation 3.48 in McGhee): 
Ditto, for h/w < 0.2, (equation 3.49 in McGhee): 
Triangular weirs (equation 3.51 in McGhee): 
From the EPANET manual by Lewis Rossman.
equation 1 in the EPANET manual: 
equation 1 related in the EPANET manual: 
equation 1 related in the EPANET manual: 
equation 1 related in the EPANET manual: 
equation 2 in the EPANET manual: 
equation 3 in the EPANET manual: 
equation 4 in the EPANET manual: 
equation 4 related in the EPANET manual: 
equation 5 in the EPANET manual: 
equation 6 in the EPANET manual: 
equation 7 in the EPANET manual: 
equation 8 in the EPANET manual: 
equation 9 in the EPANET manual: 
equation 10 in the EPANET manual: 
equation 11 in the EPANET manual: 
equation 12 in the EPANET manual: 
equation 13 in the EPANET manual: 
equation 14 in the EPANET manual: 
equation 15 in the EPANET manual: 
equation 16 in the EPANET manual: 
equation 17 in the EPANET manual: 
equation 18 in the EPANET manual: 
equation 19 in the EPANET manual: 
equation 20 in the EPANET manual: 
equation 21 in the EPANET manual: 
