It can be difficult to estimate the amount of disk space a WIMS database will use over time.  Several factors effect how a database grows:

• Number of Variables
• Frequency of data (i.e. once/day, every 15 minutes, etc...)
• Number of reports and graphics used in them
• Miscellanous Factors

NOTE: Use the attached DB_Size_Estimator.xls to try different configuations of number of variables. 

The following table displays some common databases and their size:

Plant	Typical Variables	Baseline DB size	Growth per Year
Small WWTP (<3 MGD)	200 Daily variables	8 MB	8 -15 MB
Medium WWTP (<8 MGD)	400 Daily Variable 40 Hourly Variable	15 MB	40-100 MB
Large WWTP (40 MGD)	800 Daily Variables 100 Hourly Variables	25 MB	150-250 MB
Small SWTP (<3 MGD)	100 Daily Vars 50 Hourly Vars 5 15 Min Vars	8 MB	60 - 120 MB
Small Ground Water System (<3 MGD)	50 Daily Vars	8 MB	5 - 10 MB
Medium SWTP (<8 MGD)	400 Daily Vars 200 Hourly Vars 20 15 Min Vars	15 MB	250 - 500 MB

NOTE: Use the attached DB_Size_Estimator.xls to try different configuations of number of variables. 

To calculate an "estimate" of how fast your database will grow, follow this example:

Everyday, I store four (4) - 15 minute variables for filter turbitdity, 50 hourly readings that the operators take, and up to 100 daily water quality parameters.  Therefore, I store about 2,884 ((96 *4) +(100 * 24) + 100) data points a day.

Storage required to store 2884 data points:

• [low end]  = 2 * (2884 * 130 Bytes) = 2 * 374920 Bytes ~  .7 Megabytes
• [high end] = 2 * (2884 * 200 Bytes) = 2 * 576800 Bytes ~ 1.1 Megabytes

Your daily storage requirement is going fall somewhere between high end and low end numbers above.

If your maximum database size limit is 2 GB , it will take approximately :

• [low end]  2,926 days to fill up the database
• [high end] 1,862 days to fill up the database

It has been determined that it takes on average between 130 (on the low end) to 200 (on the high end) Bytes of actual disk space required to store 1 row of data (WIMS datapoint). Each datapoint write transaction also generates 1 row of audit trail of approximately the same size. Where your system falls between the high end and low end is determined by lots of factors, which include disk allocation unit size, density of text-data, and density of index.