Average bed material load of a regime channel conforming to Lacey equations will be of the order of 500 ppm.

Lacey's regime theory is widely used in the field of open channel hydraulics to estimate the sediment transport capacity and the average bed material load of a channel. The theory is based on the concept of the critical shear stress required to initiate sediment movement and the equilibrium between sediment supply and transport capacity.

The average bed material load refers to the amount of sediment transported per unit area of the channel bed. It is typically expressed in terms of parts per million (ppm), which represents the mass of sediment per million units of water. In the case of a regime channel conforming to Lacey equations, the average bed material load is estimated to be around 500 ppm.

The Lacey equations provide relationships between channel characteristics, such as slope, discharge, and sediment characteristics, such as sediment size and specific gravity, to estimate the sediment transport capacity. These equations are derived from extensive experimental studies and have been found to be applicable to a wide range of natural and artificial channels.

The bed material load in a regime channel is influenced by various factors including channel slope, flow velocity, sediment size, and sediment concentration. Lacey's equations take into account these factors to estimate the sediment transport capacity and the resulting bed material load.

It is important to note that the estimated average bed material load of 500 ppm is an average value and can vary depending on the specific conditions of the channel and the sediment. In practice, it is common to conduct field measurements and observations to validate and adjust the estimated values obtained from Lacey's equations.

In conclusion, the average bed material load of a regime channel conforming to Lacey equations is estimated to be around 500 ppm. This value provides a useful reference for engineers and researchers in the field of open channel hydraulics to estimate sediment transport capacity and design channel systems.