VERTICAL DATUM In the Campbell River, Chart Datum rises in steps of 0.2 metres along the river to approximate Lowest Normal Tide throughout the area. Chart Datum at Boliden Westmin (Discovery Passage) is 2.92 metres below Geodetic Datum. At Baikie Slough it is 1.52 metres below Geodetic Datum and at the upriver limit of soundings on this chart it is 0.92 metres below Geodetic Datum. There is also a decrease in the range of tide along the river. At Baikie Slough, the Large Tide range is approximately 3.2 metres and at the upriver limit of soundings, it is approximately 2.7 metres.
