{"id":235,"date":"2017-11-01T16:40:00","date_gmt":"2017-11-01T16:40:00","guid":{"rendered":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/?post_type=ht_kb&#038;p=235"},"modified":"2025-03-20T19:00:14","modified_gmt":"2025-03-20T19:00:14","slug":"idf-correction-factors","status":"publish","type":"ht_kb","link":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/knowledge-base\/idf-correction-factors\/","title":{"rendered":"IDF Correction Factors"},"content":{"rendered":"\n<p>You can enter Frequency Correction Factors, (a.k.a. Runoff Coefficient Saturation Factors), Cf, with your IDF Rainfall Curves. The Cf factors can be edited on the Known Equation Coefficients screen or the Computed Coefficients screens.<\/p>\n\n\n\n<p>Cf factors are applied to the Runoff Coefficients when computing peak flows for the Rational Method. The intensities shown on your reports will not reflect this factor. The computed flows will, however. The product of C x Cf cannot exceed 1.0.<\/p>\n\n\n\n<figure class=\"wp-block-image is-style-default\"><img loading=\"lazy\" decoding=\"async\" width=\"186\" height=\"57\" src=\"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/EqRatMethod.jpg\" alt=\"\" class=\"wp-image-238\" srcset=\"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/EqRatMethod.jpg 186w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/EqRatMethod-50x15.jpg 50w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/EqRatMethod-60x18.jpg 60w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/EqRatMethod-100x31.jpg 100w\" sizes=\"auto, (max-width: 186px) 100vw, 186px\" \/><\/figure>\n\n\n\n<p>Correction Factors can be edited while you are setting up your IDF curves. Rather than clicking [Finish] just after entering or importing data, continue to click [Next] until you arrive at the Equation Coefficients screen shown below. There you can enter Cf values. Remember to click the [Apply] button.<\/p>\n\n\n\n<figure class=\"wp-block-image alignnone wp-image-226 size-full is-style-default\"><img loading=\"lazy\" decoding=\"async\" width=\"784\" height=\"394\" src=\"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff.png\" alt=\"\" class=\"wp-image-226\" srcset=\"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff.png 784w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff-300x151.png 300w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff-768x386.png 768w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff-50x25.png 50w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff-60x30.png 60w, https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-content\/uploads\/sites\/2\/2017\/11\/IDFCfCoeff-100x50.png 100w\" sizes=\"auto, (max-width: 784px) 100vw, 784px\" \/><figcaption><em>Edit the Correction Factors, Cf, on this screen<\/em><\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Editing Correction Factors<\/h2>\n\n\n\n<p>If you need to edit existing Cfs, click on the [New&#8230;] button on the Rainfall Wizard window.<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-207\" src=\"https:\/\/learn.hydrologystudio.com\/stormwater-studio\/wp-content\/uploads\/sites\/3\/2017\/10\/NewIdfBut.png\" alt=\"\" width=\"58\" height=\"62\"><br>Then Click [Next]. Then [Next] again to reach the above screen. Then enter\/edit the Cf values. Click [Apply]. Then [Finish].<\/p>\n","protected":false},"excerpt":{"rendered":"<p>How to enter and\/or edit IDF Correction Factors (CF)<\/p>\n","protected":false},"author":1,"comment_status":"closed","ping_status":"closed","template":"","format":"standard","meta":{"footnotes":""},"ht-kb-category":[27],"ht-kb-tag":[56,55],"class_list":["post-235","ht_kb","type-ht_kb","status-publish","format-standard","hentry","ht_kb_category-idf-curves","ht_kb_tag-cf","ht_kb_tag-correction-factors"],"_links":{"self":[{"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/ht-kb\/235","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/ht-kb"}],"about":[{"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/types\/ht_kb"}],"author":[{"embeddable":true,"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/comments?post=235"}],"version-history":[{"count":9,"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/ht-kb\/235\/revisions"}],"predecessor-version":[{"id":4567,"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/ht-kb\/235\/revisions\/4567"}],"wp:attachment":[{"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/media?parent=235"}],"wp:term":[{"taxonomy":"ht_kb_category","embeddable":true,"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/ht-kb-category?post=235"},{"taxonomy":"ht_kb_tag","embeddable":true,"href":"https:\/\/learn.hydrologystudio.com\/hydrology-studio\/wp-json\/wp\/v2\/ht-kb-tag?post=235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}