Northern Wasco Parks and Recreation District says it has sourced enough chlorine to open the North Wasco Aquatic Center in The Dalles Monday.  A region-wide liquid chlorine shortage due to disruptions at a major manufacturer led to the pool being forced to close.  There will an open swim Monday from 1 p.m. to 7 p.m.   The district says the pool will not be open Tuesday, but will open on other hot days as it is able to do so.  The district did say the first session of swim lessons has been canceled, refunds are being processed, and checks will be mailed out.  The district also said the Westlake chlorine plant in Longview anticipates restarting production next week, with deliveries resuming by July 1.  There will be a significant backlog of deliveries, but the district is estimating it will receive its first shipment sometime in the vicinity of July 7 to July 9.