Stage-Storage Relationship and Stage Discharge Relation and Storage Indicator Numbers

For Pond Routing, reference is made from MSMA 2nd Edition; Chapter 7 Detention Pond 

MSMA 2nd Edition

1. Stage-Storage Relationship #

For Example; at stage 1.5m; #

V = [(A₁ + A₂ ) / 2 ]  * 0.5 

   = (7275 + 7360 / 2) * 0.5 

   = 3658.75m³ + 6599m³

   = 10257.75m³ $\approx$10258m³ 

2. Stage-Discharge Relation and Storage Indicator Numbers #

For Example: let’s take H = 1.5m, #

Calculate O (m³/s) at H = 1.5m;

Note: please refer to Figure 2.8 on how to take the ‘H_o‘

V = C_o A_o (2gH_o)^0.5                  (Equation 2.6 & Figure 2.8; MSMA 2nd Edition)

    = 0.6 (2) ( 2 * 9.81 * (1.5-0.5))^0.5

    = 5.32m³/s

Calculate (S/Δt) + O/2 (m³/s)

Note: Δt is the pond routing time step, hence in this example Δt = 1min

(S/Δt) + O/2 = (10258m³ / 60sec) + 5.32m³/s

                     = 173.626 m³/s