[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-1-en-105":3,"doc-seo-563930-105":53,"doc-detail-563930-en":127},{"code":4,"msg":5,"data":6},0,"success",[7,14,19,24,29,34,39,44,49],{"id":8,"doc_module":9,"doc_module_name":10,"category_name":11,"show_sort_weight":12,"slug":13},11,1,"Template","Presentations",90,"presentations",{"id":15,"doc_module":9,"doc_module_name":10,"category_name":16,"show_sort_weight":17,"slug":18},12,"Resumes",80,"resumes",{"id":20,"doc_module":9,"doc_module_name":10,"category_name":21,"show_sort_weight":22,"slug":23},14,"Invoices",70,"invoices",{"id":25,"doc_module":9,"doc_module_name":10,"category_name":26,"show_sort_weight":27,"slug":28},15,"Posters",60,"posters",{"id":30,"doc_module":9,"doc_module_name":10,"category_name":31,"show_sort_weight":32,"slug":33},16,"Social Media",50,"social-media",{"id":35,"doc_module":9,"doc_module_name":10,"category_name":36,"show_sort_weight":37,"slug":38},17,"Forms",40,"forms",{"id":40,"doc_module":9,"doc_module_name":10,"category_name":41,"show_sort_weight":42,"slug":43},18,"Letters",30,"letters",{"id":45,"doc_module":9,"doc_module_name":10,"category_name":46,"show_sort_weight":47,"slug":48},21,"Paper Templates",5,"papers-templates",{"id":50,"doc_module":9,"doc_module_name":10,"category_name":51,"show_sort_weight":4,"slug":52},158,"General","general-158",{"code":4,"msg":54,"data":55},"ok",{"site_id":56,"language":57,"slug":58,"title":59,"keywords":60,"description":61,"schema_data":62,"social_meta":120,"head_meta":122,"extra_data":124,"updated_unix":126},105,"en","an-evaluation-of-tidal-flushing-for-shelter-island-yacht-basin-using-a-simple-tidal-prism-model-prepared-for-mr-paul-brown","An Evaluation of Tidal Flushing for Shelter Island Yacht Basin Using a Simple Tidal Prism Model - Prepared for Mr. Paul Brown","","Evaluation of tidal flushing for Shelter Island Yacht Basin addresses elevated total dissolved copper concentrations detected by the San Diego Regional Water Quality Control Board. A simple one-dimensional box model is used to estimate dilution over tidal cycles, assuming one-dimensional volume exchange and complete mixing each cycle. The model is driven by basin volume at Mean Lower Low Water derived from recent bathymetry and tidal prism volumes from measured San Diego Bay tidal ranges. Exchange efficiency is identified as the dominant uncertainty, strongly influencing predicted flushing time and the 50% concentration-change interval.",{"@graph":63,"@context":119},[64,80,102],{"@type":65,"itemListElement":66},"BreadcrumbList",[67,71,74,77],{"item":68,"name":69,"@type":70,"position":9},"https://docshare.wps.com","Home","ListItem",{"item":72,"name":10,"@type":70,"position":73},"https://docshare.wps.com/template/",2,{"item":75,"name":51,"@type":70,"position":76},"https://docshare.wps.com/template/general/",3,{"item":78,"name":59,"@type":70,"position":79},"https://docshare.wps.com/template/an-evaluation-of-tidal-flushing-for-shelter-island-yacht-basin-using-a-simple-tidal-prism-model-prepared-for-mr-paul-brown/563930/",4,{"url":78,"name":59,"@type":81,"image":82,"author":87,"headline":59,"publisher":90,"fileFormat":93,"inLanguage":57,"description":61,"dateModified":94,"datePublished":95,"encodingFormat":93,"isAccessibleForFree":96,"interactionStatistic":97},"DigitalDocument",{"url":83,"@type":84,"width":85,"height":86},"https://docshare.wps.com/thumbnails/an-evaluation-of-tidal-flushing-for-shelter-island-yacht-basin-using-a-simple-tidal-prism-model-prepared-for-mr-paul-brown/563930.png","ImageObject",442,249,{"name":88,"@type":89},"Finn","Person",{"url":68,"name":91,"@type":92},"DocShare","Organization","application/pdf","2026-10-23","2026-10-12",true,{"@type":98,"interactionType":99,"userInteractionCount":101},"InteractionCounter",{"@type":100},"ViewAction",8,{"@type":103,"mainEntity":104},"FAQPage",[105,111,115],{"name":106,"@type":107,"acceptedAnswer":108},"Why was tidal flushing for Shelter Island Yacht Basin evaluated?","Question",{"text":109,"@type":110},"The board found elevated total dissolved copper levels in the basin that exceed the state water quality criterion, prompting development of a copper TMDL. The evaluation supports estimating flushing for that TMDL development.","Answer",{"name":112,"@type":107,"acceptedAnswer":113},"What model was used to estimate tidal flushing?",{"text":114,"@type":110},"A simple one-dimensional box model was employed. It assumes one-dimensional volume exchange between the basin and adjacent waters and complete mixing during each tidal cycle.",{"name":116,"@type":107,"acceptedAnswer":117},"What most strongly affects the model’s flushing-rate estimates?",{"text":118,"@type":110},"Exchange efficiency has the largest impact on the model results. The report notes a substantial difference in predicted tidal cycles over the examined efficiency range.","https://schema.org",{"og:url":78,"og:type":121,"og:title":59,"og:site_name":91,"og:description":61},"article",{"robots":123,"canonical":78},"index,follow",{"doc_id":125,"site_id":56},563930,1792109882,{"code":4,"msg":5,"data":128},{"doc_id":125,"user_id":129,"nickname":88,"user_avatar":130,"doc_module":9,"category_id":50,"category_name":51,"doc_title":59,"doc_description":61,"doc_content":131,"file_id":132,"file_url":133,"file_type":134,"file_size":135,"view_count":101,"is_deleted":4,"is_public":9,"is_downloadable":9,"audit_status":9,"page_count":136,"language":137,"language_code":57,"site_id":56,"html_lang":57,"table_of_contents":138,"faqs":139,"seo_title":140,"seo_description":61,"update_tm":141,"read_time":73},34359740700684,"https://ap-avatar.wpscdn.com/avatar/1f400023980c374ae676?_k=1777273430885731487","An Evaluation of Tidal Flushing for Shelter Island Yacht Basin Using a  \nSimple Tidal Prism Model  \nPrepared by  \nDavid W. Moore, Ph.D.  \nMEC Analytical Systems, Inc.  \nPrepared for  \nMr. Paul Brown  \nSan Diego Unified Port District  \n30 August, 2000  \nEvaluation of Tidal Flushing for Shelter Island Yacht Basin  \nThe San Diego Regional Water Quality Control Board (SDRWQCB) has found elevated total dissolved copper levels in the Shelter Island Yacht basin (1.6 to 9.1 g/L) that exceed the state water quality criterion (3 g/L) . These findings have lead to subsequent action by the board to develop a TMDL for copper in the basin. To facilitate development ofthis TMDL the Unified Port District of San Diego in consultation with SDRWQCB directed MEC Analytical Systems, Inc. to develop a box model for estimating tidal flushing of the Shelter Island Yacht basin.  \nTo generate an estimate of tidal flushing in the Shelter Island Yacht basin a simple one-dimensional box model was employed. The model (equation 1) assumes a one-dimensional volume exchange between the system of interest and adjacent waters and that complete mixing occurs on each tidal cycle. The number of tidal cycles required to achieve a specified dilution is calculated using the following equation:  \n ln (Co/Cn)   \nN = (equation 1)  \nln (1 + VP/VL)  \nwhere N = number of tidal cycles;  \nCo = initial concentration (dimensionless);  \nCn = final concentration (dimensionless);  \nVP = Volume (ft3) of the tidal prism;  \nVL = Volume (ft3) of the basin at Mean Lower Low Water (MLLW) .  \nWhen compared to empirically derived flushing rates the model tends to be conservative (i.e., overestimate flushing rates) . However, based on a review by Walton (1983) this one-dimensional box model represents a reasonable \"back-of the envelope\"calculation for canals and marinas and compares favorably with more complex/costly physical models. Modifications have been developed over the years to account for the discrepancies between empirically derived data and estimates from the model. Gibson (1959) and Ketchum (1951) modified the above equation by dividing the system under consideration into segments and assumed different efficiencies of exchange between the segments. Kuferman (1974) modified the model to incorporate empirically derived exchange coefficients. Callaway (1981) used a decay coefficient for concentration to simulate mixing in South Beach Marina in Oregon.  \nIn order to calculate flushing for the Shelter Island Yacht basin, estimates of the basin volume at MLLW were determined from recent bathymetry by the Port of San Diego (Table 1) . The surface area estimate at MLLW was then used to calculate volume estimates for the tidal prism (Table 2) using mean and maximum tidal ranges measured in San Diego Bay (P.F. Wang et al. , 1998) . An examination of the tide charts for San Diego indicates that the median tidal range resides somewhere between the mean and the maximum (i.e., more often than not the tidal range will be between 3 to 5 feet) .  \nConsequently, use of the maximum and mean tidal range offers a reasonable approximation of the median tidal range. In calculating these volume estimates it was assumed that the surface area of the basin did not change over the tidal ranges evaluated. To estimate the number of tidal cycles required to affect a 50% change in concentration of the constituent of interest, Co was set to a value of 10 and Cn was set to a value of 5 (i.e., a 50% reduction) . Since it is unlikely that each tidal cycle results in a 100% exchange between VP and VL a range of exchange efficiencies (100 to 25%) was used to evaluate the effect of exchange efficiency on model estimates. In order to account for differences in exchange efficiency the equation was modified:  \n ln (Co/Cn)   \nN = (equation 2)  \nln (1 + ((VP/VL) x )))  \nwhere = fractional rate of exchange.  \nResults of the model estimates are provided in table 3. The number of tidal cycles required to achieve of 50% redu","cbCaisOhIH8vjitR","https://ap.wps.com/l/cbCaisOhIH8vjitR","pdf",68483,6,"English","# Evaluation of tidal flushing model\n## Box model assumptions and dilution equation\n## Model inputs: basin volume and tidal prism volume\n## Exchange efficiency and uncertainty\n## Volume estimates (Tables 1-2)\n## Model results (Table 3)","[{\"question\":\"Why was tidal flushing for Shelter Island Yacht Basin evaluated?\",\"answer\":\"The board found elevated total dissolved copper levels in the basin that exceed the state water quality criterion, prompting development of a copper TMDL. The evaluation supports estimating flushing for that TMDL development.\"},{\"question\":\"What model was used to estimate tidal flushing?\",\"answer\":\"A simple one-dimensional box model was employed. It assumes one-dimensional volume exchange between the basin and adjacent waters and complete mixing during each tidal cycle.\"},{\"question\":\"What most strongly affects the model’s flushing-rate estimates?\",\"answer\":\"Exchange efficiency has the largest impact on the model results. The report notes a substantial difference in predicted tidal cycles over the examined efficiency range.\"}]","An Evaluation of Tidal Flushing for Shelter Island Yacht Basin Using a Simple Tidal Prism Model - Prepared for Mr. Paul Brown | PDF",1791839398]