2006 hydrology manual los angeles county

We are doing hydrology study for an area in the city of santa. Location and description of property figure 1 shows the proposed location of the proposed avanti south residential development. Site location the site is located at the intersection of avenue r and division street and is currently an. Existing peak runoff flows and volumes during a 50year storm event for. The lacdpw hydrology manual 2006 requires projects to have drainage facilities that meet the urban flood level of protection. Appendix g preliminary hydrology and stormwater drainage. Storm frequency conversion factors based on rainfall frequencies.

Use county approved hydrology methods and programs, see 2006 hydrology and sedimentation manual available on the following web address to download the computer program used to calculate your hydrology information mora, by woodcrest is no longer acceptable to county standards. Lack of stream flow data made it difficult to establish standards. The drainage areas for the proposed development were determined based on the proposed streetland flow areas and the existing offsite topography. The burned runoff coefficients versus rainfall intensities were input into the modrat program as new soil types. Results matching of public works page 3 of 6 lac open data. Open public viewer for 2017 noaa rain zone map 31 zones, 10, 25, 50, and 100yr rainfall contours and 2005 lidar data. A watershed is the land area where water collects and drains onto a lower level property or drains into a river, ocean, or other body of water. Rainfall and soil characteristics for the project site are given in isohyetal map figure lacdpw. Solano county water agency 810 vaca valley parkway, suite 203 vacaville, ca 95688 tel. Price list for selected publications countywide construction contracting policy manual design manuals hydraulic design manual hydrology manual 2006.

Grading manual 2006 edition dana point city council wayne rayfield mayor lara anderson mayor pro tem james v. Methodology the rational method and modified rational method are empirical computation procedures for. What is the difference between modrat and mora and if not. Rainfall and soil characteristics for the project site are given in isohyetal map figure lacdpw 1hi. Design procedure, predesign data, hydrology and alignment, main line hydraulics, catch basin design, preliminary plans, construction controls, final plans, design check prior to advertising for bids. Rainfall depth was determined for the 10year and 50year storm event using the isohyetal maps in the. Google earth 2010, federal emergency mamagement agency fema september 2008, impact sciences, inc. Woodcrest engineering obtained the source code and developed it for personal computers. The modrat and mora software programs both do modified rational hydrology calculations.

Each area was analyzed for acreage, impervious cover, and time of concentration according to the rational method. Examples provide guidance on using the hydrologic methods. F6, the existing stormwater runoff rate at the project site is approximately 152. The remaining portion of the site was designed to accommodate a 50. The proposed onsite runoff will be intercepted via catch basins strategically located throughout the site. We assigned an impervious factor of 6% which is the same designation used by ackerman et al. Hydrology manual ventura county public works agency. The standards set forth in this manual govern all hydrology calculations done under pub lic works jurisdiction. Open 2017 hydrology manual 24 mb, pdf appendix e files provided below download 2017 hydrology manual 24 mb, zip go to 2018 vcrat2. Per the orange county local drainage manual, all building pads shall be. Dk engineer, corporation hydrologylid report for juniper. Contains rainfall data, reservoir data, water conserve, spreading grounds, debris basins, runoff data, erosion control.

The methods used are the rational method for subarea tilne of concentration computation and the modified rational method for flow routing through the drainage watershed and runoff computation. Before starting a hydrology study on the site indicated above. Method analysis was performed and the appropriate calculations are. Appendix h hydrology analysis lancaster, california. Drainage area a1 drains south into wilshire boulevard and drainage area a2 flows west into fairfax avenue. The soil numbers are indicated by the class field and are to be used in accordance with the 2006 hydrology manual which clearly describes the application of the soil numbers as it applies to our hydrologic method. We are doing hydrology study for an area in the city of. The manual contains current standards and procedures, examples, runoff coefficient charts, and maps of rainfall isohyets and soil types. Grading manual 2006 edition dana point, california. The software packages accepted by public works are found in chapter 15 of the 2006 hydrology manual available online at. The predominant soil type for the proposed site is 002, see figure 3. Before starting a hydrology study on the site indicated. This method is described in the 2006 hydrology manual which is available online at the following link.

Storm frequency conversion factor q x k q 11 2yr 5yr 10yr 25yr 50yr k 0. Hydrology calculation for peak flow rate for the total drainage area based on rational method is included in appendix v. More detailed information related to class numbers and their meaning can be found. A rational method analysis was performed and the appropriate calculations are provided herein. Appendix g preliminary hydrology and stormwater drainage study. Runoff rates were calculated for 50year storm events. The purpose of this report is to show that the proposed development will not have any negative effects on the existing hydrologic condition of the site and any downstream facilities.