| DBHYDRO Browser |
| Frequently Asked Questions |
| Question: |
What is DBHYDRO? |
| Answer: |
DBHYDRO is the South Florida Water Management District corporate environmental database which stores hydrologic, meteorologic, hydrogeologic, and water quality data. This corporate database is a one-stop source for all historical and up-to-date environmental data for the region covered by the District. The database includes the not only data from South Florida Water Management District but also data from other agencies such as United States Geologic Survey, National Oceanic and Atmospheric Administration, and Everglades National Park. |
| Question: |
What kind of data is in DBHYDRO? |
| Answer: |
Not only does DBHYDRO contain environmental data, but is also stores additional information about sites, water control structures, and stations where data are collected. Accurate descriptions are available for most of the sites, giving the user information on the hydrologic basin, latitude, longitude, state plane coordinates, county, section, township, range, and many other useful attributes. |
| Question: |
How big is DBHYDRO? |
| Answer: |
To give an idea of the amount of data in DBHYDRO we offer the following: DBHYDRO contains more than 5 million water quality results, more than 30 million daily hydrologic values, and hydrogeologic data from more than 9000 boreholes. |
| Question: |
Is the data up-to-date? |
| Answer: |
The data on DBHYDRO is up-to-date. That is, as data is posted, it is immediately available to the public. |
| Question: |
What is DBHYDRO Browser? |
| Answer: |
DBHYDRO Browser is a web-based application that allows users to browse DBHYDRO using one or more criteria to generate a summary listing of time series. The user can then select one or more time series of interest and have the time series data dynamically displayed on their screen in tables or graphs. Alternatively, the data may be saved to a file and post-processed by the user. |
| Question: |
Who can use the system? |
| Answer: |
Any one with internet access can use the system. |
| Question: |
Do I need to get a user id and password from the District to access the data? |
| Answer: |
No, the data is available immediately. |
| Question: |
I want the data sent to me in a file rather that displayed on the screen. What kind of file downloads are available? |
| Answer: |
You can always get a fixed format file and, in some cases, a comma separated file or an Adobe Acrobat file is available. |
| Question: |
What is a DBKEY? |
| Answer: |
A DBKEY is a the DBHYDRO system assigned unique identifier for a data set (or time series). A DBKEY is to a data set what a social security number is to a person. |
| Question: |
Do I have to know the DBKEY in order to access the desired data? |
| Answer: |
No, you may access the data in a variety of fashions. Access can be by site name (general location), station name (specific to a site), project name (for water quality data), data type (flow, rainfall, water level, etc.), agency (SFWMD, USGS, etc.), hydrologic basin, county, etc... Criteria may be applied in combination to be as general or as specific as you like. |
| Question: |
Can I open multiple windows to access my data faster. |
| Answer: |
Yes, but be aware that the limiting factor may be your connection to the system. This is especially true if you are using a dial-up connection. |
| Question: |
Is the data safeguarded? |
| Answer: |
Yes. If you are an internet user you are accessing a read-only version of the database that is further protected by password and other means. |
| Question: |
Is there a training class for DBHYDRO? |
| Answer: |
Yes. The District offers an in-house class. The course number is IRD4000 and the course name is "DBHYDRO Users". Sign up through your training coordinator. |
| Question: |
Can I get large amounts of data? |
| Answer: |
Yes. Large batch retrieval capability is available. Batch retrievals are suggested for retrieval of long periods of instantaneous values. Web browser technology tends to "time out" during long queries. Some interactive retrievals are on a first-come first-served basis but each batch retrieval receives its own dedicated computer resources. |
| Question: |
Where is the map-based interface? |
| Answer: |
Each individual station, on its individual station information page, has a link to Google Maps.
Internet map based access is available at http://glades.sfwmd.gov/
Intranet access is enabled two ways. The intranet EMAPS application at http://imsprod1/GEO-Viewer2.1/map.aspx?Project=Emaps&Service=Emaps is one method. The internal District's Google Earth Enterprise Client (EC) also provides access to DBHYDRO through the environmental monitoring and operations layers. These map-based web sites will be integrated with the DBHYDRO more in the near future. |
| Question: |
What is "preferred" data? |
| Answer: |
Some data has a recorder type of PREF. These specific data sets have undergone an additional level of QA/QC by the SFWMD and should be used wherever applicable. |
| Question: |
What coordinate system and projection is used for X-Y coordinates? |
| Answer: |
X-Y coordinates are NAD83 HARN Florida State Plane East Zone coordinates in units of feet. |
| Question: |
Which vertical datum is used? |
| Answer: |
NGVD29 is the official vertical datum for the South Florida Water Management District and DBHYDRO data. The South Florida Water Management District is developing a NGVD29 to NAVD88 migration plan. Some data may be in NAVD88 and is explicitly labeled as such. Information on the Vertical Datum Upgrade Program is at www.sfwmd.gov under the "Technical Data and Documents" section. |
| Question: |
What is OLECAS? |
| Answer: |
OLECAS is the On-Line Environmental Chemist Analysis System, a tool to assist in the quality assurance process for the SFWMD water quality laboratory. If you are part of the routine monitoring program you may wish to contact mvadde@sfwmd.gov to get on the distribution list for the daily lab "outlier" report. |
| Question: |
What does a negative value for a water quality analytical test result mean? |
| Answer: |
A negative value indicates the value was below detection limits. This fact is verified by the remark code for the result in question. |
| Question: |
Is all SFWMD environmental data available through DBHYDRO Browser? |
| Answer: |
Requests for related data categorized as research or regulatory may be made via public records request. |
| Question: |
Is all the data usable? |
| Answer: |
Data usability depends on the needs of the individual user. Most data are collected to meet stated data quality objectives for some primary purpose. However, these objective may or may not be sufficient for secondary uses of data. When in doubt contact the agency to whom the data is attributed. |
| Question: |
What is a DCVP Station ID? |
| Answer: |
A DCVP Station ID is an identifier for a single time series in the District's internal hydrometeorologic data processing system. Most data stored in DCVP are instantaneous readings. These readings are identified in DBHYDRO Browser as those having a frequency code of "BK". The SFWMD computes mean daily values for these instantaneous readings (where meaningful) and stores the daily values with a frequency code of "DA". |
| Question: |
How do I cite DBHYDRO in my works-cited list? |
| Answer: |
A generic web reference to DBHYDRO Browser following the Modern Language Association style:
DBHYDRO Browser, South Florida Water Management District, date site accessed, http://my.sfwmd.gov/portal/page?_pageid=2235,4688582&_dad=portal&_schema=PORTAL>
Information regarding citing web sources in MLA style may be found at: http://www.mla.org/style_faq4
|
| Question: |
What does it mean when a report indicates my data has been QA'ed? |
| Answer: |
QA'ed data is that which has undergone routine Quality Assurance procedures. Other data which has not undergone such procedures may be labeled as Provisional. |
| Question: |
What is the difference between salinity, conductivity, and specific conductance and what are the correct units of measure? |
| Answer: |
Since 1978, the Practical Salinity Scale, adopted by oceanographers and the UN, is the conductivity ratio of a sea water sample to a standard KCl (potassium chloride) solution. It just so happens that 35 ppt = 35 psu (practical salinity units). The reason for the adoption of this new scale is that ppt, or parts per thousand, refers to a gravimetric measurement of salinity by weighing out 1000 g (1 kg) of seawater, evaporating the water, and weighing the residue. Typically, for every 1000 g of seawater, approximately 35 g of salt would remain. Hence the units of parts per thousands. However, this method of determining salinity is cumbersome. Thanks to the Law of Constant Proportions (Marcet's Principle) of ions in seawater, a titrametric method (Mohr-Knudsen titration) was developed using chloride as an indicator of salinity. Based on this chloride content or chlorinity, salinity can be calculated:
Salinity = 1.80655*Chlorinity (in ppt)
Since most salinity measurements have shifted from an analytical method to direct measurement using conductivity, the new salinity scale is therefore more appropriate.
There is a difference between conductance and conductivity:
Conductance is the reciprocal of resistance and therefore its unit is 1/(ohms) or mhos or S (for Siemens)
Conductivity is the reciprocal of resistivity. Its unit is expressed as 1/(ohm m) or mhos/m or S/m
Members of the scienitific community have sometimes confused these measurements and have used them interchangeably. Even the Class III water quality standards refer to specific conductance expressed as micromhos/cm rather than to specific conductivity. |
