Facts and figures
Overview of facts and figures from the Noorderzijlvest Water Authority.
Key figures Noorderzijlvest
| Noorderzijlvest working area | Groningen north of the Eems canal, northwest Drenthe, and the Frisian part of the lake Lauwersmeer area |
| Size of our management area | approx. 144,000 hectares (= 1,440 km²) |
Number of councils our region | 9 local councils:
|
| WFD catchment | Nedereems, north Rhine |
| Natura 2000 areas in our management area | Lake Leekstermeer area: Norgerholt Fochteloërveen |
| Number of inhabitants in our region | 415,325 (as at 31 December 2025) |
| Number of pollution units (PUs) | 420,108 reported units |
| Noorderzijlvest employees | 393 employees. That amounts to 346 staff positions. |
| Lowest point in our region | -2.50 m NAP |
| Lowest water level in our region | -3 m NAP |
| Highest point in our region | +14.00 m NAP |
| Highest water level in our region | +12.10 m NAP |
Surface waters
Key figures Noorderzijlvest
| Our primary watercourses | 2,223 km |
| Our ditches under inspection | 1,320 km |
| Our balancing lakes (storage in case of disaster) as defined under Environment and Planning Act | 2,418 ha |
| Our surface water pumping stations | 151 |
| Mills capable of milling in our management area | 17 |
| Our water authority weirs | 829 |
| Our locks | 17 |
| Our inlets | 473 |
Flood defences (dykes and flood embankments)
Key figures Noorderzijlvest
| Primary flood defences Lauwersoog to Delfzijl (the Ommelanderzeedijk) | 69 kilometres |
| Regional and other flood defences | 486.7 kilometres |
Water treatment
Key figures Noorderzijlvest
| Treated wastewater per year | 50,096,940 m³ (= over 50 billion litres) |
| Number of pollution units | 420.108 |
| Our wastewater treatment plants | 11 |
| Our sludge dewatering plant | 1 |
| Number of transport pumping stations | 112 sewage pumping stations under our own management |
| Our pressure pipes | 380 km |
| Sewage overflows in our area | 453 |
| IBAs inour management area | 1217 |