Tenders Are Invited For Engineering Services – Service Contract Relating To The Revision Of Alert Thresholds In The Context Of The Announcement, Monitoring And Forecasting Of Floods And Floods, As Well As Their Definition Under The Law Of Walloon Municipalities Impacted By Floods.

Engineering Services – Service Contract Relating To The Revision Of Alert Thresholds In The Context Of The Announcement, Monitoring And Forecasting Of Floods And Floods, As Well As Their Definition Under The Law Of Walloon Municipalities Impacted By Floods.. The Object Of The Contract Is The Provision Of Services Relating To The Development And Application Of A Coherent And Reproducible Methodology For The Revision Or Definition Of Alert Thresholds Intended For The Announcement, Monitoring And Forecasting Of Floods And Floods, As Well As Their Definition Under The Law Of Walloon Municipalities Impacted By Floods. Description Of The Services To Be Performed: The First Objective Is To Define And/Or Verify The Consistency Of The Flow Thresholds Used By The Hydrological Management Department Of The Spw Mi In The Context Of Flood Forecasting And Flood Warning. This Involves Validating, Setting Or Revising: - The Threshold Values ​​Of The Flow Rates Causing The First Overflows, As Well As Those Corresponding To The Justification For Transitions To The Pre-Alert And Alert Phases. The Return Period Flow Of 100 Years Or That Of The Largest Known Flood Will Complete The Information Equivalent To An Extreme Flood Threshold; - The Division Of The Walloon Territory Into Hydrologically Homogeneous Watersheds/Sections For The Dissemination Of The Pre-Alert And Alert Phases. A Coherent And Reproducible Methodology Will Be Developed Based On That Implemented To Define Vigilance Levels In France. It Must Follow A Basic Approach With Three Components To Define The Thresholds: 1. The Hazard: Physical Characterization Of Floods Based On The Return Period And/Or Local Hydraulic Particularities Such As The Flow Corresponding To The First Overflows And The Most Extreme Historical Flood. 2. The Issues: Assessment Of Potential Effects On People, Property And Activities. By Determining Thresholds On The Number Of Issues Affected Triggering An Alert Phase, We Will Consider That A Threshold Exceeded For An Issue Triggers This Phase. 3. The Context: Exceptional Consideration Of Temporary Elements. For Each Threshold Value, A Transition Zone Will Also Be Determined To Take Into Account The Uncertainties Linked To The Characterization Of The Hazard And The Issues. Currently, For The Territory Of Wallonia, The Dgh Applies 3 Phases (1St Overflows, Pre-Alert And Alert) For 42 Watersheds / Sections Based On 45 Hydrological Forecast Points And Approximately The Same Number Of Points Where Historical Flow Thresholds Exist. Given The New Developments Underway At The Dgh And The Needs In Times Of Crisis, It Is Expected That The Method Deployed Here Will Apply To 85 So-Called “Main” Measuring Stations Within The Framework Of This Market. The Second Objective Is To Define These Four Threshold Values ​​And Their Transition Zones At The Municipal Level So That Each Walloon Municipality Crossed By One Or More Navigable And Non-Navigable Watercourses Of The 1St Category (Around 190 Municipalities / 261), Can Position Their Own Local Phases. For The Application Of The Methodology To The Walloon Territory, The Following Points Are