BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

For a bulkhead located such that the design wave is not broken at the toe underany lake levels, the scour conditions and bulkhead design must be carried outby engineering firms that regularly perform such services.Second, the wave run-up and overtopping values must be calculated. Theminimum crest elevation is established as follows.Calculate the design wave height at the toe of the bulkhead Ht, including theeffects of scour on the water depth.The freeboard Rc of the wall – that is, the crest elevation above the still waterlevel including wave setup – must obey both of the following criteria:First, fewer than 2% of the waves should overtop the wall using Equation 2.2(CEM Equation VI-5-33), which shows the relationship between probability ofovertopping per incoming wave (Pow).2 R cP exp 2% 0.91(Equation 2.2)ow Ht Second, the average discharge of water Q, calculated with Equation 2.3 due towaves that do overtop the wall must not be dangerous to pedestrians or causedamage to buildings (CEM Equation VI-5-28, Table VI-5-6).Q 43 R c10 cfs/foot0.082gHtexp 3 ‐5 3 Ht 10m /s/mstandardunitsmetricunits(Equation 2.3)8.2.4 INSTALLATIONDue to the site specific requirements and general design complexity, bulkheads,and lake walls must be designed by a licensed professional civil engineer andinstalled by qualified professional construction personnel.8.2.5 MAINTENANCEBulkheads must be inspected periodically (annually to biannually) for signs ofscour at the top, base, or sides and repaired immediately.TRPA BMP HandbookCHAPTER 8: Shorezone Protective Structures and BMPs2012 8.2 Bulkheads and Lake WallsPage 8-27