TAtslc 1-1. Mos~ Gutdclincs for ScAfloor Ollcrations Subjcct N'bhicatiore Comiscnits A gcnscral soils ticsign NwAal lFacilitkcs linginccring Command, Design handbook ittnded prim MaInual OM.7. Soil mechanics foundationsissnd earth manly fur usc an land a struclures, Mar 1971 many procedures apphicable to undwa-ter use Naval CMvi Engineering Laboratory. TechnicA Repiort Most dctailecd guide R-799, tetrim design guidclincs for seafloor footing, book for seafloor foot-Foundations by 11. G. I Icrnann and 11.J. Valcnt. Oct 1973 ing dcsign Nival Civil Engineering I.3boratory. Tocchnical Noi A simplifiedl version of N*1 246, Vou~ndstions for small scafloor installation. TK-799 by It. G. I krrmann, Seps 1972 North American Rockwcll corporation. I andbook of A abokfrlrr ocean ind underwater nctering, Chapter 8, 1969 (~ri~3r) ie supported) structures A handbook for drag Naval Pacilities Hngineering Command, lDesign anchors and associated ,Manual DNI26. hlarbor and coastal facilities, Jul 1968 mooring equipmcni, sonic design informition Anchrin ciit Egincrig Ibornryhanbookforuplft. Colictc summary of Anchrin Ciil ngiccrng abortor, IUndookforuplft-uplift-rcsisting anchors resisting anchors, by R. J. Taylor, 1). joncs, and and decsign irnformation R. .M. Bcard, Sep 1975 (holding capacity inrormation is out of datc) Civil Engincering lsboratory, Long-termn holding Revised holding-eapacity capacity of statically loaded anchors in cohecsive soils, predliction procedares by R. hi. 11card (1979) Naval Civil Enginccring Lboratory, Technical Rclort Mlethiod for predicting Breakout R-755, Unaided breakour of partially embedded foc necded to dislodge objccts from cohecsive seafloor soils, by If. J. Lee,:i mcd ojt Fcb 1972 a meddojc dComplce entries will be found in Section 8, REFERENCES.

The Coastal Engineering Technical Note (CETN) herein describes a database of cost and performance data from sand bypassing projects created as the initial step of developing an overall methodology for evaluating fixed sand bypass plant potential at coastal inlets. BACKGROUND: Discontinuities in the shoreline, i.e., natural inlets, stabilized inlets and harbors, all interrupt the longshore transport of littoral sediments. At inlets and harbors used for navigation, most of which are stabilized with jetties, trapping of littoral sediments in jetty fillets, flood and ebb tidal shoals and the navigation channel cause two main problems. One problem is erosion of downdrift beaches. When sand is trapped in the navigation channel, the second problem is reduced navigation capabilities. Artificial sand bypassing, hereinafter referred to as sand bypassing or simply as bypassing, is the man-induced transfer of sand from the jetty fillets, shoals, or navigation channel to the downdrift beaches to mitigate the problems associated with the inlet or harbor. The majority of sand bypassing is done in association with navigation dredging where sand removed from the navigation channel is placed directly on downdrift beaches or in the nearshore zone. Among U.S Army Corps of Engineers (Corps) coastal navigation projects, sand bypassing using fixed plants is relatively rare. This is also true from a worldwide perspective. Fixed-plant sand bypassing might be applied to more sites. However, the effort required to estimate costs and performance is significantly greater with fixed plants than simply modifying a navigation dredging contract for downdrift beach placement. The goal of the "Sand Bypassing Costs and Performance" Work Unit in the Corps Coastal Navigation and Storm Damage Reduction Research Program is to develop a standard methodology for calculating costs of fixed sand bypass systems using standard Corps cost-estimating techniques. Methods to predict performance of the fixed plant bypass systems (volume bypassed and bypassing rate), will also be provided. The costs and benefits of a fixed plant can then be directly compared to sand bypassing using conventional dredged and beach placement allowing Districts to relatively easily and at a modest cost to compare fixed plants with conventional dredging for maintenance of coastal inlets and downdrift beaches. In theory, this will facilitate selecting the optimum method for inlet maintenance, lowering costs and increasing benefits.

The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products.

Photogrammetry has been applied as a technique to monitor the stability of dolosse on the Manasquan Inlet, New Jersey jetties. These jetties were rehabilitated between 1979 and 1982 with 16-ton steel-reinforced dolosse. The jetties have been exposed to a number of storms since 1982, including a design-level storm in March 1984. The photogrammetric measurements have provided a detailed record of the magnitude and direction of dolos movements in response to these storm events. Standard leveling techniques have been used to check the accuracy of the elevation data derived from photogrammetry. This paper describes the methods used in this monitoring effort and the results obtained from the photogrammetric measurements. Also presented are data on the structural integrity of the steelreinforced dolosse.