**EDIT**

**Why this *is* a world-building query**. If I had framed this as, "In my world where magic requires the expenditure of energy, a powerful wizard decides to open a path through a large lake,etc. The world I am supposing is that God himself can create and destroy energy (or has an infinite supply) but still *uses* energy to do his miracles and acts of creation. This is different from simply magicking things in and out of existence as the Bible perhaps implies.

---

> 
> The Red Sea has a surface area of roughly 438,000 km2 (169,100
>  mi2),[1](https://i.stack.imgur.com/z1mM3.png) is about 2250 km (1398 mi) long and, at its widest point,
>  355 km (220.6 mi) wide. It has a maximum depth of 3,040 m (9,970 ft)
>  in the central Suakin Trough,[3] and an average depth of 490 m (1,608
>  ft).
> 
> 
> 

[![enter image description here](https://i.stack.imgur.com/z1mM3.png)](https://i.stack.imgur.com/z1mM3.png)

**Assumptions for the purposes of this question**

We cross where the sea is 100km wide, the depth is 500m at its maximum, the seabed is an arc of a circle.

The density of Red Sea Brine is 1100 kg/m3

The corridor for the Israelites is 10m wide. They can walk at a steady pace of 4kph regardless of slope.

[![enter image description here](https://i.stack.imgur.com/ZrqOh.png)](https://i.stack.imgur.com/ZrqOh.png)

**Question**

If we simplify by saying they all leave and arrive at the same time: 

(a) How long will God have to hold the waters apart and 

(b) What will be his total energy expenditure both for opening the corridor and then holding it open?