INTERNATIONAL HYDROGRAPHIC REVIEW 
MAY 2020 
76 
4. Practical implications 
New nautical products that use BSCD2000 are identified by the chart datum name BSCD2000 <X> , 
where <x> denotes the respective national height system realization according to Table 2 (e.g., 
BSCD2000 RH200 ° for Sweden). 
The main consequence for the mariner is that the charted depth in BSCD2000 changes by a con 
stant value compared to the old zero level. The offset is individual per country or per map sheet, 
depending on the former MSL-related chart datum. In most cases, this offset will be negative, 
since the new zero level of the BSCD2000 is in general below the present day MSL for the Baltic 
Sea (see Figure 6 for a generalized visualization and Figure 7 for a map of the national MSL reali 
zations currently in use). However, for charts of areas strongly affected by postglacial uplift and 
referring to very old MSL realizations, the change to BSCD2000 may be considerable. Figure 1 
gives an impression of the land uplift rates according to the model NKG2016LU (Vestol et al. 
2016). 
MSL 
(resp. old 
Chart Datum) 
Water level correction (old CD) 
Water level correction (BSCD2000) 
Charted depth 
(old CD) 
Charted depth 
(BSCD2000) 
BSCD2000 
Figure. 6: Schematic cartoon of the old MSL-based chart datum and the new BSCD2000 
At the same time, real-time water level information (water level observations, corrections to the 
charted depths, forecasts, etc.) will also be changed accordingly to comply with the new chart da 
tum. This also allows for a better and easier monitoring and prediction of the current and future 
sea states out at sea, since real-time oceanographic models can be simply interpolated 
(Figure 8), whereas switching between the sometimes far-distant mareographs and their local 
references may introduce a large error margin (Figure 9). 
The transition from the numerous MSL-based chart datums of each country to BSCD2000 is a 
complex and stretched process from the first decisions to the final implementation in the chart 
products. In particular, paper charts need longest to be switched due to the long production 
cycles. Some countries, like Estonia, have already informed mariners about the changes to 
BSCD2000 and have published the first products. Others, like Denmark, are about to formally