Each lot will be the subject of a separate allocation. The interconnection project plans to secure the various resources of the former Saint-Omer CA perimeter, namely the North boreholes (Serques, Tilques and Salperwick) to the South boreholes (Blendecques, Arques and Hallines). The project foresees:

- interconnection and securing of six catchment fields,

- creation of a 4000 m reservoir 3 to respond to the lack noted in the diagnostic study,

- supply and laying of more than 11 km of pipelines,

- creation of a 300 m booster 3 / h near the Glacis reservoir.

This work will make it possible to secure all the AEP networks of the CAPSO urban service (Longuenesse, Arques, Blendecques, Saint-Omer, Saint-Martin-lez-Tatinghem, Salperwick), ie around 50,000 inhabitants.

This lot is split into three phases:

- 1: projected Hallines reservoir - Blendecques,

- 2: Blendecques - Glacis reservoir,

- 3: securing Wizernes.

Construction of the Chartreux booster and replacement of the Hallines F2 drilling equipment.

Construction of a 4000 m reservoir 3 in the town of Hallines - civil engineering - VRD - works equipment.