This data layer is part of a collection of GIS data created for the Okanagan Mainstem Floodplain Mapping Project. Notes below apply to the entire project data set.***Download Size is 12.5 GBGeneral Notes1. Please refer to the Disclaimer further below.2. Please review the associated project reports before using the floodplain maps: Northwest Hydraulic Consultants Ltd. (NHC). 2020. ‘Okanagan Mainstem Floodplain Mapping Project’. Report prepared for the Okanagan Basin Water Board (OBWB). 31 March 2020. NHC project number 3004430. Northwest Hydraulic Consultants Ltd. (NHC). 2021. ‘Okanagan Mainstem Floodplain Mapping Project – Development of CGVD1928 Floodplain Mapping’. Letter report prepared for the Okanagan Basin Water Board (OBWB). 30 March 2021. NHC project number 3006034.Northwest Hydraulic Consultants Ltd. (NHC). 2022. ‘Supplemental to the Okanagan Mainstem Floodplain Mapping Project – Current Operations Flood Construction Levels for Okanagan and Wood-Kalamalka Lakes’. Report prepared for the Okanagan Basin Water Board (OBWB). Final. 16 August 2022. NHC project number 3006613.3. These floodplain mapping layers delineate flood inundation extents under the specific flood events. Tributaries are not included in mapping.4. The mapped inundation is based on the calculated water level. Freeboard, wind effects, and wave effects have been added to the calculated water level where noted.5. Where noted, a freeboard allowance of 0.6 m has been added to the calculated flood water level. It has been added to account for local variations in water level and uncertainty in the underlying data and modelling.6. Where noted, the FCL (or COFCL) included in lake mapping layers includes an allowance for wind setup and wave runup based on co-occurrence of the seasonal 200-year wind event. The wind and wave effects extend 40 m shoreward to delineate the expected limit of wave effects. Beyond this limit the FCL (or COFCL) is based on inundation of the flood event without wave effects. Wave effects have been calculated based on generalized shoreline profile and roughness for each shoreline reach. Site specific runup analysis by a Qualified Registrant may be warranted to refine the generalized wave effects shown, which could increase or decrease the FCL (or COFCL) by as much as a metre.7. Underlying hydraulic analysis assumes channel and shoreline geometry is stationary. Erosion, deposition, degradation, and aggradation are expected to occur and may alter actual observed flood levels and extents. Obstructions, such as log-jams, local storm water inflows or other land drainage, groundwater, or tributary flows may cause flood levels to exceed those indicated on the maps.8. The Okanagan floodplain is subject to persistent ponding due to poor drainage. Persistent ponding is not covered by the flood inundation mapping.9. For flood level maps (water level and inundation extents):a. Layers for each flood scenario describe inundation extents, water surface elevations, and depths.b. The calculated water level has been extended perpendicular to flow across the floodplain; thus mapping inundation of isolated areas regardless of likelihood of inundation; whether it be from dike failure, seepage, or local inflows. Distant isolated areas may be conservatively mapped as inundated. Site specific judgement by a Qualified Professional is required to determine validity of isolated inundation.c. Filtering was used to remove isolated areas smaller than 100 m2. Holes in the inundation extent with areas less than 100 m2 were also removed. Isolated areas larger than 100 m2 are included in GIS data layers and are shown on maps if they are within 40 metres of direct inundation or within 40 metres of other retained polygons.d. Okanagan Dam breach, dam overtopping, or overtopping and breaching of Penticton Beach were not modelled. Inundation downstream of the Okanagan Dam on the left bank floodplain is based on river modelling with the assumption that Okanagan Lake levels will not overtop Lakeshore Drive and adjacent high ground. For the design flood scenarios, inundation mapping on the right bank of the Okanagan River from the Okanagan Dam downstream to the Highway 97 bridge and Burnaby Avenue is based on additional lake and river modelling. For other flood scenarios, river and lake inundation has been mapped separately and has not been integrated on the right bank. Inundation mapping on the right bank is based on river modelling as far as the most upstream modelled river cross section.10. For flood hazard maps (depth and velocity):a. Layers describe flood water depths and velocities. Depths and velocities are based on the maximum values from three modelled scenarios: all dikes removed, left bank dikes removed, and right bank dikes removed. Depths do not include freeboard.b. All hazard layers were modelled with the same parameters and boundary conditions as the design flood.11. Flood modelling and mapping is based on a digital elevation model (DEM) with the following coordinate system and datum specifications: Universal Transverse Mercator Zone 11-N (UTM Zone 11-N), North American Datum 1983 Canadian Spatial Reference System epoch 2002.0 (NAD83 CSRS (2002.0)), Canadian Geodetic Vertical Datum 2013 (CGVD2013), Canadian Gravimetric Geoid model of 2013 (CGG2013). FCL values are presented on the maps in both CGVD2013 and CGVD1928 vertical datums. CGVD1928 values are based on the following specifications: NAD83 CSRS (2002.0), CGVD1928, Height Transformation version 2.0 epoch 1997 (HTv2.0 (1997)). COFCL and COFCL values are presented only in CGVD2013.12. The accuracy of simulated flood levels is limited by the reliability and extent of water level, flow, and climatic data. The accuracy of the floodplain extents is limited by the accuracy of the design flood flow, the hydraulic model, and the digital surface representation of local topography. Localized areas above or below the mapped inundation maybe generalized. Therefore, floodplain maps should be considered an administrative tool that indicates flood elevations and floodplain boundaries for a designated flood. A qualified professional is to be consulted for site-specific engineering analysis.13. Industry best practices were followed to generate the floodplain maps. However, actual flood levels and extents may vary from those shown. OBWB and NHC do not assume any liability for variations of flood levels and extents from that shown.Data Sources Design flood events are based on hydrologic modelling of the Okanagan River watershed. The hydraulic response is based on a combination of 1D and 2D numerical models developed by NHC using HEC-RAS software, and NHC SWAN models. The hydraulic models are calibrated to the 2017 flood event and validated to the 2018 flood event; due to limits on data availability the hydrologic model is calibrated using data from 1980-2010. The digital elevation model (DEM) used to develop the model and mapping is based on Lidar data collected from March to November 2018 and provided by Emergency Management BC (EMBC), channel survey conducted by WSP in March, April, and June 2019, and additional survey data. See accompanying report for details NHC (2020).DisclaimerThis document has been prepared by Northwest Hydraulic Consultants Ltd. for the benefit of Okanagan Basin Water Board, Regional District of North Okanagan, Regional District of Central Okanagan, Regional District of Okanagan-Similkameen, Okanagan Nation Alliance for specific application to the Okanagan Mainstem Floodplain Mapping Project, Okanagan Valley, British Columbia, Canada (Ellison, Wood, Kalamalka, Okanagan, Skaha, Vaseux, and Osoyoos lakes and Okanagan River from Okanagan Lake to Osoyoos Lake). The information and data contained herein represent Northwest Hydraulic Consultants Ltd. best professional judgment in light of the knowledge and information available to Northwest Hydraulic Consultants Ltd. at the time of preparation, and was prepared in accordance with generally accepted engineering practices.Except as required by law, this document and the information and data contained herein are to be treated as confidential and may be used and relied upon only by Okanagan Basin Water Board, Regional District of North Okanagan, Regional District of Central Okanagan, Regional District of Okanagan-Similkameen, Okanagan Nation Alliance, its officers and employees. Northwest Hydraulic Consultants Ltd. denies any liability whatsoever to other parties who may obtain access to this document for any injury, loss or damage suffered by such parties arising from their use of, or reliance upon, this report or any of its contents.Data Layer List and Descriptions<!--· River / Lake Model Boundary -River / Lake Model Boundary (NHC): Boundary between Okanagan River and Okanagan Lake modelling and mapping areas for design and flood mapping.Recommended Design Flood (gates open): Ellison, Skaha, Vaseux, and Osoyoos lakeso Lake Shoreline Flood Construction Level (FCL) Zone – Recommended Design Flood with Freeboard and Wave Effect (NHC): Zone defined based on approximate shoreline and the wave breaking boundary plus a buffer; FCLs defined by zone along shoreline; shoreline FCLs take precedence over lake inundation FCLs.o Lake Flood Construction Level (FCL) Zone (Inundation Extent) – Recommended Design Flood with Freeboard (NHC): Design flood inundation extent with freeboard. Design event varies by lake, plus wind setup, plus mid-century climate change; plus freeboard 0.6m.o Lake Inundation Extent – Recommended Design Flood without Freeboard (NHC): Design flood inundation extent without freeboard. Design event varies by lake, plus wind setup, plus mid-century climate change.o Depth Grids§ Ellison Lake Depth – Recommended Design without Freeboard (NHC): ELLISON LAKE: 200-YEAR MID-CENTURY. Design flood depth

This hosted feature layer has been published in RI State Plane Feet NAD 83. Conservation ecologists have coined the term Ecological Land Units (ELU) to describe and map the physical properties of landscapes. Typically, ELUs are defined by the geology, soils, elevation, and landform (hilltop, hillside, valley). A specific ELU has a unique combination of soils, geology, landform, and elevation. ELUs are derived from soil and elevation data using a GIS. It was important that we used readily available data and we kept the derivation of ELUs as simple as possible. After consulting the published literature and conferring with expert soil scientists and plant ecologists, we focused on two aspects of soils, soil drainage class and soil texture. Soil drainage class is very good at distinguishing wet versus dry habitats. Soil texture (sandy, silty, loamy, etc.) is an important habitat component for plants. Using USDA SSURGO (State Soil Survey Geographic Database) data that is readily available from RIGIS, we created a raster dataset (50 feet cell size) of the different soil drainage classes and another raster dataset of the soil texture classes. There are many properties of soils that are available to use for analyses such as this, for example stoniness, depth to bedrock, etc. The two factors we chose are extremely important soil properties in supporting different plant communities. Landform represents where a location is with respect to elevation, slope, and aspect (direction a hillside is facing). Landform distinguishes hilltops, hill sides, valley bottoms, etc. We used the RIGIS digital terrain model as our source of elevation data to measure landform. Landform classes were identified using GIS modeling of slope, aspect, and elevation. The final ELU map is made by adding together the raster datasets for landform, drainage class, and soil texture. Because we were careful with our encoding system, the sum of the three rasters provides us a composite of the individual datasets. For example, a location that is a well-drained (code value 2000) and consists of gravelly sand (code value 100) a sits on a hilltop (code value 21) and would combine to be ELU 2121 (2000+100+21). This process yielded 204 unique ELUs for the state of Rhode Island. Examination of a cumulative distribution function (CDF) of the ELUs showed that most of the ELUs were small and did not occur very often. Conversely, 20 ELUs were quite common and encompassed almost 85% of the land area of RI.Find out more about Mapping ELUs

DownloadA daily extract of the NPDES Structures dataset is available for download as a zipped file geodatabase.BackgroundAs a government agency that owns and maintains separate storm sewer systems, the Maryland State Highway Administration (SHA) is mandated to file a National Pollutant Discharge Elimination System (NPDES) permit with the Maryland Department of the Environment (MDE). The permit requires the inventory, inspection, and maintenance of SHA stormwater infrastructure. SHA is responsible for maintaining storm drain infrastructure on more than 5,000 miles of roadway statewide. SHA has developed a program consisting of SHA personnel, data managers, and subject matter experts to support the permit requirements and maintain these roadways. The tasks involved in the SHA NPDES data collection program are often completed by engineering consultants for SHA. The data are organized into a series of drainage systems with stormwater management facilities that are interconnected, allowing for flow-tracing function through distinct systems. A drainage system is defined as a series of storm drain structures or point features (i.e., manholes, inlets, endwalls) that connect hydraulically through conveyance features such as pipes and / or ditches. Closed and open storm drain structures are connected by pipe and ditch conveyance to create the drainage system. Stormwater management facilities (SWMF), also known as stormwater best management practices (BMP) are inventoried with the storm drain system. A system can include both open and closed storm drain features. StructuresPhysical stormwater structures to be identified and inventoried include headwalls, endwalls, cross culverts, pumping stations, stormwater risers and weirs, inlets, pipe connections, and manholes. Storm drain structures are represented as point features in the database. Several database features are included that are not existing physical structures, but are employed to facilitate connection of drainage systems in the database. For detailed descriptions of each feature, refer to the SHA Book of Standard for Highway & Incidental Structures, Category 3 “Drainage.” Storm drain structures within SHA ROW are inventoried. Information on private storm drain structures will need to be collected if a private system ties into SHA-owned storm drain features. The only structures that are not inventoried within SHA ROW are single residential driveway culvert end structures (See below for more details), bridge inlets, under drains, roof drainage, or other private tie-ins with the exception of the first or last structure from a private storm drain system and curb opening. If an under-drain pipe has an end structure (such as an endwall), then the structure is inventoried. Curb openings are only inventoried when affecting the drainage area for a BMP or major outfalls. If it is deemed necessary to include a curb cut in the database, the curb cut is captured as an inlet feature with comments identifying the feature as a curb opening. A curb opening is not a COG or COS inlet with an open back, but simply a cut in the curb where sheet flow is exiting impervious. The following are brief discussions of the structures in the data. See Chapter 2 of the Maryland SHA Stormwater NPDES Program SOP for more information, figures, and descriptions of each field. End / Head StructuresAn end / head structure is any structure at the upstream or downstream end of a culvert or pipe. These can include headwalls, endwalls, end sections, and projection pipes. Often the end / head structure is designated on the contract sheets and field verified. When contract plans are not available for a roadway, the SHA Book of Standard for Highway & Incidental Structures should be referenced if structure types are unfamiliar with field teams. Outfall areas are not to be inventoried, but will be analyzed during the inspection process. Headwalls (HW) are structures that are placed at the upstream end of pipes and culverts to provide a stable or hydraulically desirable entrance to the conveyance. Headwalls are usually concrete but can be constructed of wood or masonry, such as brick or concrete block. Wall structures on the upstream side of a culvert or pipe are inventoried as headwalls. Plan sheets may designate the upstream end of a pipe or culvert as an endwall, but these structures should be inventoried as headwalls. All wall-end structures at the upstream end of a pipe or culvert should be inventoried as headwalls. Endwalls (EW) are structures that are placed at the downstream end of pipes and culverts to provide a stable or hydraulically desirable exit to the conveyance. Endwalls are usually concrete, but can be constructed of wood or masonry such as brick or concrete block. All wall structures on the downstream side of a culvert or pipe are inventoried as endwalls. Plan sheets may designate the downstream end of pipe or culvert as a headwall, but these structures should be inventoried as endwalls. All wall-end structures at the downstream end of a pipe or culvert should be inventoried as endwalls. End Sections (ES) are structures that transition the ends of pipes into slopes and provide stability to the pipe entrances and outflows. End sections do not affect the hydraulic capacity or efficiency of the pipes. End sections can be constructed of concrete, metal, or plastic (HDPE). End sections can either be inventoried at the upstream or downstream end of a pipe. Projection Pipes (PP) are not physical structures but represent the upstream and downstream end of a pipe if an end structure on a pipe does not exist. Projection pipes are captured spatially as a feature and represent the ends of pipes. Inlet StructuresInlets are structures that collect storm drain runoff. Inlets convey the runoff to closed storm drain systems, open conveyance, or outfalls. There are many different types of inlet structures, and all are discussed in the SHA Standard Design Manual and should be reviewed prior to conducting an inventory. Spring heads are also inventoried as inlets. Inlets (IN) are hydraulic structure chambers below surface grade that collect storm drain runoff. An inlet either has a grate or open sides / curb to allow runoff to enter the storm drain system. Inlets are often constructed of concrete, masonry brick, or concrete block. Spring Heads (SH) are inventoried as inlets. Spring heads are inventoried only where they emerge and are connected to a storm drain system. Spring heads are inventoried because they provide evidence for the presence of ground water for dry weather flows during illicit discharge field screening operation. Spring heads may be identified from contract drawings or identified during the field inventory. Spring heads are mostly found in rural areas. Connection StructuresA connection structure is a storm drain structure that connects conveyance (pipes and ditches) within a system and is not an inlet, riser, weir, or pumping station. These can include manholes, ditch intersections, junction boxes, pipe connections, wye connections, capped inlets, pipe bends, and pipe directions. Because field crews are not required to open manhole lids and enter closed storm drain structures, no designation type is necessary for connection structures. All of the attribute data for these structures will be collected from contract drawings, including connection material and top of manhole elevations. The existence of connection structures should be field verified for spatial accuracy, even though the attributed data will be collected from contract drawings. For structures that are buried or paved over, a GPS point is to be recorded at the best estimated location in the field based on contract plan sheets. The verification of attribute table data for structures that cannot be verified in the field will be completed based on plan sheet information. This also holds true for structures that are buried or cannot be accessed; the attribute data should be obtained from plan sheets. Manholes (MH) are hydraulic structures that connect pipes through a system. They are used as access points to a system, to change direction or invert elevations for pipes, as a junction to change pipe size and / or material, and as a junction of multiple pipes to a single pipe. Manholes are frequently paved over or buried, but are still inventoried. Unless it is certain that the manhole does not exist, the manhole is inventoried. Manholes with lids that have designed holes to allow runoff to enter are inventoried as manholes and not inlets. Ditch Intersections (ID) are geographic representations of where ditches meet, begin, or end a system and are captured as point features. These features are used to define the extents of ditches. Junction Boxes (JB) are underground hydraulic structures that connect pipes through a system. They are used to change direction or invert elevations for pipes, to change pipe size and / or material, and to connect multiple pipes to a single pipe. Identifying junction boxes in the field is difficult because these structures are usually buried with no part of the structure exposed to the surface. Junction boxes are only inventoried from contract drawings and should never be assumed in the field, unless the field crew is certain the structure is a junction box. If the field crew suspects that pipes are merging together and no contract plans are available to confirm this, the connection should be inventoried as a pipe connection and not a junction box. Pipe Connections (PC) are locations throughout the conveyance of a system where two or more pipes connect. A pipe connection is also captured at the location where a closed storm drain pipe connects to a culvert or stream crossing. Wye Connections (YC) are hydraulic structures that join two pipes together within a system’s conveyance. Wye connections will be identified from contract drawings and should not be assumed in the field. Instead of assuming a wye