River Habitat Survey (RHS) data from rivers and streams surveyed in 2007 as part of the Countryside Survey project. River Habitat Survey (RHS) is an assessment of the physical structure of freshwater streams and rivers based on a standard 500m length sample unit. It does not require specialist geomorphological or botanical expertise but consistent recognition of features included on the form is essential. To ensure consistency of recording all surveyors must be accredited, and recording follows standard protocols. Data were collected under the Countryside Survey long term monitoring project managed by the Centre for Ecology & Hydrology. The Countryside Survey is a unique study or 'audit' of the natural resources of the UK's countryside. The sample sites are chosen from a stratified random sample, based on a 15 by 15 km grid of GB. Headwater stream surveys have been carried out in 1990, 1998 and 2007 with repeated visits to the majority of sites. The countryside is sampled and surveyed using rigorous scientific methods, allowing us to compare new results with those from previous surveys. In this way we can detect the gradual and subtle changes that occur in the UK's countryside over time. In addition to headwater stream data, soil data, habitat areas, vegetation species data and linear habitat data are also gathered by Countryside Survey.

This record is for Approval for Access product AfA434. "River Habitat Survey (RHS) is the Environment Agency standard for collecting data on the physical character and quality of river habitats across the UK. This dataset provides survey details and summary results for river habitat surveys carried out from 1994 to present. This dataset is a subset of AfA286 River Habitat Survey. Since 1994 approximately 19,000 surveys have been carried out in England. The bulk of surveys were carried out between 1994 to 1997 and 2006 to 2008. Surveys are still carried out for specific drivers, for example assessing habitat availability and Water Framework Directive. For further information on the survey methodology the RHS manual can be downloaded from www.gov.uk. Surveys conducted prior to 2003 should not be compared with surveys conducted after 2003 as survey methodology changed significantly in 2003. River names may be in English, Welsh or Gaelic. This dataset no longer contains data owned by Natural Resources Wales (NRW). To request data that relates to Wales please contact NRW. Dimensions are intended to provide context for these habitat surveys. They should not be used for other purposes. The following information has been excluded from the survey data supplied to you because there is a risk that we might be disclosing personal data. If a customer has a particular interest in a particular site/survey examples of the type of information we may be able supply are: • General description of the survey • Surveyors name • Weirs/sluices, culverts, outfalls/intakes, dams, abstractions, hydroelectric power • Where channel is choked by vegetation or a debris dam impeding flow • Tipped materials and landfill • Presence of sewage and pollution • Gravel extraction

Please note: We have discovered some errors in the HQA in-stream channel vegetation sub-score and the HMS Culverts sub score that users of our data need to be aware of:

1. In-stream channel vegetation HQA sub-score: This error has now been fixed - all surveys carried out after 12/07/2017 will be correct. However, stored, historic calculations are not automatically updated. The error only applies under certain criteria (where present or extensive is entered in Spot-check 11, but spot-check’s 1-10 are not listed as present or extensive for the same vegetation category) and will only affect the HQA sub-score by a few points.

2. 1994 surveys - In-stream channel vegetation HQA sub-score (Submerged vegetation). No fix in place – all recorded submerged vegetation category entries are excluded from any 1994 surveys. This error will only impact the HQA scores by 1-2 points

3. HMS Culvert Score error. No fix in place. This error affects sites where a culvert is recorded in a spotcheck(s) and Bank Material, Bank modification and channel substrate are not listed as NK or NV. This can affect the scores on a much larger scale as our database is failing to add on 50 points per culverted spot-check, that fulfil these criteria.

In 2009, the Kootenai Tribe of Idaho released and implemented the Kootenai River Habitat Restoration Master Plan. This plan aimed to restore, enhance, and maintain the Kootenai River habitat and landscape to support and sustain habitat conditions for aquatic species and animal populations. In support of these restoration efforts, the U.S. Geological Survey, in cooperation with the Kootenai Tribe of Idaho, conducted high-resolution multibeam echosounder bathymetric surveys as a baseline bathymetric monitoring survey on the Kootenai River near Bonners Ferry, Idaho. Three channel patterns or reaches exist in the study area: braided, meander, and a transitional zone connecting the braided and meander reaches. Bathymetric data were collected to: (1) survey unmapped portions of the Kootenai River; (2) re-survey portions of the Kootenai River to quantify changes in the channel; and (3) monitor aggradation and degradation of the channel bed at specific cross-sections within the braided re ...

Results of in-stream habitat surveys (Downie et al 1998 method), summarized by stream reach, for DFG surveys conducted between 1994 and 2001 (inclusive) in the Russian River Basin (CalWater 2.2.1 hydrologic area), Central Coast Region. Sampled habitat parameters, including pool type, frequency and depth; substrate class; bank vegetation composition and canopy closure; and in-stream cover, were measured at the unit scale and summarized to stream reach.

MoRPh Rivers is a field survey for monitoring river channel and riparian physical habitats at scales that can complement biological surveys. The survey was developed through a partnership between Cartographer Studios, Queen Mary University of London and the Environment Agency.You can download technical documents relating to the MoRPh survey from the MoRPh website, https://modularriversurvey.org. These documents include a manual that fully describes the survey and also a document, "MoRPh Index Calculations 2020", that explains how the fourteen indicators that are automatically generated from each MoRPh survey are calculated.The MoRPh survey is applied to a short length or "module" of river that is approximately two channel widths in length. The survey is designed to be applied to the small (≤30m wide) single thread river channels that are typical of England. Within each river module the survey records the physical and vegetation structural features and human interventions and pressures observed across the river bed, the channel edge – water margins, the bank faces and the bank tops of a river to a distance of 10m.The observations collected in each MoRPh survey are summarised into fourteen indices:Channel CharacteristicsINDEX 1: Number of present/extensive flow typesINDEX 2: Highest energy present/extensive flow typeINDEX 3: Number of present/extensive bed material typesINDEX 4: Coarsest present/extensive mineral bed material typeINDEX 5: Average alluvial bed material size (phi units)INDEX 6: Average alluvial bed material size classINDEX 7: Extent of superficial bed siltationINDEX 8: Channel physical habitat complexityINDEX 9: Number of aquatic vegetation morphotypesRiparian Characteristics (Bank Face and Bank Top)INDEX 10: Riparian physical habitat complexityINDEX 11: Riparian vegetation structural complexityHuman Pressures and ImpactsINDEX 12: Degree of human pressure imposed by bank top land coverINDEX 13: Channel reinforcementINDEX 14: Non-native invasive plant extentIf you have any queries about this data please contact the Modular River Survey TeamAcknowledgement: Copyright 2016-Present Cartographer Studios Ltd and Modular River Survey Contributors

The objective of the priority habitat map in England is to:• help organisations protect the most natural remaining examples of rivers from further impacts on natural processes, and • highlight any aspects of habitat integrity (hydrological, chemical, physical, biological) that could most usefully be improved. The priority river habitat map that has been produced is an English interpretation of the UK definition of priority river habitat, focusing on naturalness as the principal criterion in recognition of the vital importance of natural processes in delivering sustainable riverine habitats and supporting characteristic biodiversity.Full metadata can be viewed on data.gov.uk.

This dataset includes 2023 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcuttii) in the Santa Ana River, California.

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An Innerspace 456 single-beam echosounder in conjunction with a Trimble® differential Global Positioning System (DGPS) and HYPACK® navigation software, and Ashtech Z-Xtreme and Trimble® R8 GNSS receivers was used to survey 7 chutes and 3 backwaters on the Missouri River yearly from 2011-13. These chutes and backwaters are located on the Missouri River between Newcastle, Nebraska and Rulo, Nebraska in the States of Nebr., Iowa, and Mo. Surveys of chutes consisted of topographic and bathymetric data collected along transects spaced 30.48 m apart from high bank to high bank. Surveys of backwaters consisted of topographic and bathymetric data collected along a transect grid of 76.2 m spacing. The format of this data is point data. The data were collected by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers Omaha District as part of the Missouri River Habitat Assessment and Monitoring Program.

Some of Natural Resources Wales (NRW) core ecology datasets are held in the WISKI Kisters Ecology (KiEco). KiEco provides a central repository for some of NRW's ecological monitoring data. The database holdings include data on fish species, River Habitat Surveys, invasive species, marine benthic species and habitat monitoring, and freshwater ecology. KiEco was developed in NRW to take over the required functions of the legacy Environment Agency Wales (EAW) databases, such as Biosys National Fish Population Database (NFPD) and Ecosys.

An Innerspace 456 single-beam echosounder in conjunction with a Trimble® differential Global Positioning System (DGPS), HYPACK® navigation software, and Ashtech Z-Xtreme and Trimble® R8 Global Navigation Satellite System (GNSS) receivers was used to survey 7 chutes and 3 backwaters on the Missouri River yearly from 2011-13. These chutes and backwaters are located on the Missouri River between Newcastle, Nebraska and Rulo, Nebraska in the States of Nebraska, Iowa, and Missouri. Surveys of chutes consisted of topographic and bathymetric data collected along transects spaced 30.48 m apart from high bank to high bank. Surveys of backwaters consisted of topographic and bathymetric data collected along a transect grid of 76.2 m spacing. The data were collected by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Omaha District as part of the Missouri River Habitat Assessment and Monitoring Program.

description: To address the need for baseline inventories of biota and abiotic features, the Columbia River Fisheries Program Office (CRFPO) conducted fish and aquatic habitat surveys at the Sheldon-Hart Mountain NWR Complex. The goal was to establish a baseline of fish community and habitat information for the watersheds of the primary streams supporting native fish at each refuge. The objectives were to document which fish species were present, determine the watersheds that were occupied by these species, to describe the distribution of these fish within various watersheds, and characterize aquatic habitat. In addition, a final objective was to establish and use a systematic, quantitatively rigorous, sample framework and approach that can standardize future assessments of changes in fish occupancy, fish distribution, and aquatic habitats.We surveyed the Virgin Creek and Fish Creek watersheds at Sheldon NWR, as well as the Guano Creek and Rock Creek watersheds at Hart Mountain NAR. To guide surveys in these watersheds, we developed a sample framework and identified three tiers (upper, middle, and lower) in the watersheds and sample reaches within each tier. The survey protocol consisted of two primary activities: surveying for fish at reaches where conditions were conducive to electrofishing; and characterizing habitat attributes at sample reaches.; abstract: To address the need for baseline inventories of biota and abiotic features, the Columbia River Fisheries Program Office (CRFPO) conducted fish and aquatic habitat surveys at the Sheldon-Hart Mountain NWR Complex. The goal was to establish a baseline of fish community and habitat information for the watersheds of the primary streams supporting native fish at each refuge. The objectives were to document which fish species were present, determine the watersheds that were occupied by these species, to describe the distribution of these fish within various watersheds, and characterize aquatic habitat. In addition, a final objective was to establish and use a systematic, quantitatively rigorous, sample framework and approach that can standardize future assessments of changes in fish occupancy, fish distribution, and aquatic habitats.We surveyed the Virgin Creek and Fish Creek watersheds at Sheldon NWR, as well as the Guano Creek and Rock Creek watersheds at Hart Mountain NAR. To guide surveys in these watersheds, we developed a sample framework and identified three tiers (upper, middle, and lower) in the watersheds and sample reaches within each tier. The survey protocol consisted of two primary activities: surveying for fish at reaches where conditions were conducive to electrofishing; and characterizing habitat attributes at sample reaches.

These data are from a study of juvenile salmonid use of off-channel habitats in the lower Cedar River conducted in the spring of 2023 by the King County Water and Land Resources Division, Science and Technical Support Section. This study was funded by grant from the Puget Sound Partnership (agreement number 2023-35), along with internal King County funds from the River and Floodplain Management Section and the Ecological Restoration and Engineering Services Unit. Fish observations were made via nighttime snorkeling while the physical habitat data for each snorkel unit were collected during the day. For details regarding the data collection methods and study results, see the report found here: https://your.kingcounty.gov/dnrp/library/2024/kcr3634.pdf. For other questions about these data, contact Aaron David (adavid@kingcounty.gov) or Rebekah Stiling (rstilling@kingcounty.gov).The dataset consists of four CSV files that contain the fish snorkel counts and habitat survey data for each sample unit, along with one geopackage file that contains all spatial GIS data for in the project. See below for details regarding the CSV files."Cedar_OC_fish_data_2023_06_07.csv" contains the fish data for each snorkel unit. Below are the names of the variables contained in this file and descriptions of what the variables represent.Project_name - Short name of the research project.Date_sampled - The date a survey took place (mm/dd/yyyy).Reach - The reach sampled during an individual survey. Could be one of four reaches: Riverbend, Rainbow Bend, Jan Rd, and Van Ness. Riverbend and Jan Rd are habitat restoration and flood-risk reduction projects implemented by King County in 2022. Rainbow Bend is a habitat restoration project completed in 2013. Van Ness is a naturally formed side channel complex with some human impacts.River_flow - The river discharge (ft3/s) during a survey as recorded by the Cedar River at Renton USGS gauge (12119000).Event_notes - Notes about individual survey/sampling events.Transect_ID - A unique identifier for each habitat data collection/snorkel survey unit. This identifier can be used to join or merge the different datasets together.Unit_ID - A unique identifier for each habitat data collection/snorkel survey unit within an individual survey. However, this identifier can not be used to distinguish units across surveys.Habitat_type - Whether a snorkel survey unit was within a flow-through side channel or a backwater.Area_surveyed - The area of the snorkel survey unit, in square meters.Transect_notes - Notes about individual snorkel survey units.Pass - An indicator of whether or not a unit was snorkeled twice by separate individuals to estimate uncertainty around our snorkel counts. A blank cell indicates that a unit was only snorkeled once. A 'One' indicates the first snorkel pass for a unit that was snorkeled twice, while a 'Two' indicates the 2nd pass for a unit that was snorkeled twice.Observers - The initials of the individual who snorkeled a unit.Species_code - Three letter abbreviations for fish observed in each snorkel unit. An empty cell indicates no fish were observed in that unit. CHK = Chinook salmon; COH = Coho salmon; COT = Cottid/sculpin; DAC = Dace; LMP = Lamprey; MWF = Mountain whitefish; TRT = Trout (rainbow trout/steelhead or cutthroat trout); SOC = Sockeye salmon; TSB = three-spine stickleback; UNK = Unknown.Age - The estimated age of the observed juvenile salmonids based on their size and the time of year. Only recorded for Chinook salmon, Coho salmon, and Trout. Sub-yearling = 0+; yearling or older = 1+.Number - The number of fish observed. An empty cell indicates no fish were observed in that unit.Length_class - Estimated length bins for juvenile salmonids and cottids in millimeters.Fish_notes - Notes about observed fish."Cedar_OC_habitat_data_2023_06_07.csv" contains the habitat measurements for each snorkel unit. Below are the names of the variables contained in this file and descriptions of what the variables represent.Project_name - Short name of the research project.Date_sampled - The date a survey took place (mm/dd/yyyy).Reach - The reach sampled during an individual survey. Could be one of four reaches: Riverbend, Rainbow Bend, Jan Rd, and Van Ness. Riverbend and Jan Rd are habitat restoration and flood-risk reduction projects implemented by King County in 2022. Rainbow Bend is a habitat restoration project completed in 2013. Van Ness is a naturally formed side channel complex with some human impacts.River_flow - The river discharge (ft3/s) during a survey as recorded by the Cedar River at Renton USGS gauge (12119000).Event_notes - Notes about individual survey/sampling events.Transect_ID - A unique identifier for each habitat data collection/snorkel survey unit. This identifier can be used to join or merge the different datasets together.Unit_ID - A unique identifier for each habitat data collection/snorkel survey unit within an individual survey. However, this identifier can not be used to distinguish units across surveys.Habitat_type - Whether a snorkel survey unit was within a flow-through side channel or a backwater.Transect_notes - Notes about individual snorkel survey units.Width - The width of the wetted off-channel habitat feature in meters, measured at three locations for each snorkel survey unit.Depth - Water depth in meters, measured at three representative locations within each snorkel unit.Velocity - Water velocity (cm/s), measured at 0.6 x the water depth at three representative locations within each snorkel unit.Cover_percent - A visual estimate of the percentage of a snorkel unit that had cover within the water or up to 0.5 m above the unit. Cover estimates ranged from 0% to 100%, in 10% increments. Elements that were considered cover included large wood, riparian vegetation, and undercut banks, but not the interstitial spaces between or under large cobble, riprap, or boulders."Cedar_OC_wood_data_2023_06_07.csv" contains the large wood counts for each snorkel unit. Below are the names of the variables contained in this file and descriptions of what the variables represent.Project_name - Short name of the research project.Date_sampled - The date a survey took place (mm/dd/yyyy).Reach - The reach sampled during an individual survey. Could be one of four reaches: Riverbend, Rainbow Bend, Jan Rd, and Van Ness. Riverbend and Jan Rd are habitat restoration and flood-risk reduction projects implemented by King County in 2022. Rainbow Bend is a habitat restoration project completed in 2013. Van Ness is a naturally formed side channel complex with some human impacts.River_flow - The river discharge (ft3/s) during a survey as recorded by the Cedar River at Renton USGS gauge (12119000).Event_notes - Notes about individual survey/sampling events.Transect_ID - A unique identifier for each habitat data collection/snorkel survey unit. This identifier can be used to join or merge the different datasets together.Unit_ID - A unique identifier for each habitat data collection/snorkel survey unit within an individual survey. However, this identifier can not be used to distinguish units across surveys.Habitat_type - Whether a snorkel survey unit was within a flow-through side channel or a backwater.Area_surveyed - The area of the snorkel survey unit, in square meters.Diameter_class - Large wood diameter class bin. Our only diameter bin was >10cm.Length_class - Large wood length class bin. Our only length bin was >2m.Wood_count - The count of large wood pieces within individual snorkel survey units."Cedar_OC_snorkel_units_2023_06_17.csv" contains the distance from the nearest connection to the mainstem river for each snorkel survey unit. Below are the names of the variables contained in this file and descriptions of what the variables represent.fid - A unique identifier for each habitat data collection/snorkel survey unit generated by a GIS.Reach - The reach sampled during an individual survey.Date_sampled - The date a survey took place (mm/dd/yyyy).Unit_ID - A unique identifier for each habitat data collection/snorkel survey unit within an individual survey. However, this identifier can not be used to distinguish units across surveys.Habitat_type - Whether a snorkel survey unit was within a flow-through side channel or a backwater.Area_m2 - The area of the snorkel survey unit, in square meters.Distance_m - The distance from the nearest connection to the mainstem Cedar River to the edge of the snorkel survey unit, in meters.Notes - Notes about individual snorkel survey units.

An Innerspace 456 single-beam echosounder in conjunction with a Trimble® differential Global Positioning Satellite system (DGPS), HYPACK® navigation software, and Ashtech Z-Xtreme and Trimble® R8 Global Navigation Satellite System (GNSS) receivers was used to survey 7 chutes and 3 backwaters on the Missouri River yearly from 2011-13. These chutes and backwaters are located on the Missouri River between Newcastle, Nebraska and Rulo, Nebraska in the States of Nebraska, Iowa, and Missouri. Surveys of chutes consisted of topographic and bathymetric data collected along transects spaced 30.48 m apart from high bank to high bank. Surveys of backwaters consisted of topographic and bathymetric data collected along a transect grid of 76.2 m spacing. The data were collected by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Omaha District as part of the Missouri River Habitat Assessment and Monitoring Program.

The layers within this geodataset describe physical habitat characteristics in the North and South Fork Shenandoah rivers. They represent conditions during summer low-flow periods when canoeing was possible.The data are derived from GPS field surveys and GIS editing to commplete habitat units around islands or river bends.

[This dataset is embargoed until August 31, 2025]. This dataset contains monthly/annual time series of species-specific abundances and covariates for 137 targeted larval/juvenile fish surveys at sites in a range of English lowland rivers. Larval/juvenile fish data come from two different sources: The Environment Agency’s (EA) National Fish Population Database (NFPD) between 1974 and 2017 and a dataset created by the University of Hull (UoH) between 1984 and 2017 inclusive. Biological data consists of density estimates of each fish species from each survey (per metre squared) and also the average length of specified species at the end of their first year of growth. Covariate data include habitat quality indicator (River Habitat Survey), climatic variables (Gulf Stream and North Atlantic Oscillation indices), land-use change, river hydrology, water temperature, effluent dilution factor and concentrations of chemical determinands. This dataset was created as larvae and juveniles may be particularly useful indicators and respond differently than older fish to environmental stressors. The work was supported by the Natural Environment Research Council (Grant NE/S000100/2). Full details about this dataset can be found at https://doi.org/10.5285/c904c5f0-7f21-4759-a7d4-c262da230b53

In 2009, the Kootenai Tribe of Idaho released and implemented the Kootenai River Habitat Restoration Master Plan. This plan aimed to restore, enhance, and maintain the Kootenai River habitat and landscape to support and sustain habitat conditions for aquatic species and animal populations. In support of these restoration efforts, the U.S. Geological Survey, in cooperation with the Kootenai Tribe of Idaho, conducted high-resolution multibeam echosounder bathymetric surveys as a baseline bathymetric monitoring survey on the Kootenai River near Bonners Ferry, Idaho. Three channel patterns or reaches exist in the study area: braided, meander, and a transitional zone connecting the braided and meander reaches. Bathymetric data were collected to: (1) survey unmapped portions of the Kootenai River; (2) re-survey portions of the Kootenai River to quantify changes in the channel; and (3) monitor aggradation and degradation of the channel bed at specific cross-sections within the braided reach and transitional zone. The bathymetric data will be used to update and verify flow models, calibrate and verify sediment transport modeling efforts, and aid in the biological assessment in support of the Kootenai River Habitat Restoration Master Plan. The data for each study reach were produced in LAZ format supported by most geospatial software. First release: December 2019 Revised: January 2023 (ver. 4.0)

One of the two datasets that make up the Priority River Habitat Map. Under the UK BAP definition all headwaters potentially form part of the priority habitat definition. The headwater resource can be a significant proportion of the river habitat network, accounting for the large majority of total river length. The headwater areas selected as most natural by land cover comprise a relatively large proportion of the upland headwater resource but a very small proportion of the lowland resource. The headwater analysis is the least certain component of the naturalness analysis – for example, highly natural headwater streams running through very small catchment areas, often wooded, would not be detectable by the analysis that has been undertaken. Equally, land cover is a crude measure of naturalness and various types of impact on river habitat are not well correlated with it (e.g. abstraction pressure, point source pollution). These issues can only be addressed through local interpretation of the final priority habitat map. Attribution statement: © Natural England copyright. Contains Ordnance Survey data © Crown copyright and database right [year].

description: An Innerspace 456 single-beam echosounder in conjunction with a Trimble differential Global Positioning System (DGPS), HYPACK navigation software, and Ashtech Z-Xtreme and Trimble R8 Global Navigation Satellite System (GNSS) receivers was used to survey 7 chutes and 3 backwaters on the Missouri River yearly from 2011-13. These chutes and backwaters are located on the Missouri River between Newcastle, Nebraska and Rulo, Nebraska in the States of Nebraska, Iowa, and Missouri. Surveys of chutes consisted of topographic and bathymetric data collected along transects spaced 30.48 m apart from high bank to high bank. Surveys of backwaters consisted of topographic and bathymetric data collected along a transect grid of 76.2 m spacing. The data were collected by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Omaha District as part of the Missouri River Habitat Assessment and Monitoring Program.; abstract: An Innerspace 456 single-beam echosounder in conjunction with a Trimble differential Global Positioning System (DGPS), HYPACK navigation software, and Ashtech Z-Xtreme and Trimble R8 Global Navigation Satellite System (GNSS) receivers was used to survey 7 chutes and 3 backwaters on the Missouri River yearly from 2011-13. These chutes and backwaters are located on the Missouri River between Newcastle, Nebraska and Rulo, Nebraska in the States of Nebraska, Iowa, and Missouri. Surveys of chutes consisted of topographic and bathymetric data collected along transects spaced 30.48 m apart from high bank to high bank. Surveys of backwaters consisted of topographic and bathymetric data collected along a transect grid of 76.2 m spacing. The data were collected by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Omaha District as part of the Missouri River Habitat Assessment and Monitoring Program.

The Helford River is a small marine inlet in south Cornwall which was formed by the flooding of a river valley subsequent to the last ice age. Historically the waterway has long been associated with human activities, providing a trade route for the surrounding villages and towns. At the present time however, activities are largely of a recreational nature, although some oyster farming and fishing still takes place. For several decades, the Helford River has been visited by collectors and scientists who were interested in the marine biota found in the vicinity. The biological reputation of the area grew, and was recognized by the Nature Conservancy Council as a result of there programme of intertidal surveys which took place during the 1970's. Since then, however, there has been a distinct deterioration in the quality of the majority of intertidal habitats and communities found within the Helford River, concentrating on sublittoral habitats, and to assess the nature conservation importance of the area using standard criteria. Survey work consisted of in situ recording of conspicuous species and collection of sediment samples for biological analysis, by using a pipe dredge and also a suction sampler. Abundances of conspicuous species were defined by the use of abundance scales and the information obtained was directly comparable to that for other areas. Sediment samples were sieved over a 1 mm mesh. Animals were picked out, identified and counted. Photographs were taken during fieldwork to illustrate habitats, communities and species. Habitats and communities present were classified into seven intertidal types and twenty subtidal types each of which is described. The distribution of habitats and communities is discussed, and for selected areas, the present biological data have been compared with ealier records. Features of the Helford River have been compared with those of other marine inlets. Communities have been provisionally graded as of Local, Regional, National or International conservation importance. It is generally acknowledged that many of the communities have been damaged and the assessment takes no account of their former condition. However, the recent designation of the Helford Voluntary Marine Conservation Area creates a potential for the rehabilitation of affected habitats. Records currently considered sensitive have been removed from this dataset.