Monitoring to Meet Your Goals

What type of environment do you want to monitor?

• Address conditions such as wave action, tidal range, flow rates, and flood levels in order to select the appropriate equipment and platform
• Consider access to water
• Consider water quality concerns: high turbidity, floating material, algae or other vegetation, hydrogen sulfide, etc.

How often can you visit the site?

• Is the site offshore or in a very remote location? If so, it may be very expensive to visit for maintenance.
• To reduce costs associated with site visits, consider sensors, accessories, and platforms that allow for the longest possible maintenance intervals. Power consumption and biofouling are the primary limitations for most equipment.

What technical resources are available to maintain the equipment?

• How many technicians are available to the monitoring program, and how much time will they have to support the monitoring station? Some platforms have a relatively low up-front cost but will require 2-3 times more site visits to maintain.
• If the site is not easy to access, consider stations that offer longer maintenance intervals.

What is your budget?

• Be sure to consider both up-front capital costs and on-going operations and maintenance costs.

What temporal resolution do you require?

• Do not monitor more frequently than is necessary. Is a data point every 15 minutes, 1 hour, 4 hours, or 1 day adequate?
• The longer between samples, the lower the power demand and often the longer between maintenance visits. Telemetry costs can also be less.
• However, very dynamic systems require greater resolution.

What parameters do you need to monitor?

• Although you want to make the most of your monitoring station, do not deploy sensors that you do not need. Each sensor has its own calibration and maintenance requirements and will require time and effort.
• Some sensors are more durable than others. By adding sensors that you do not need, you will often shorten your deployment intervals.

What accuracy, detection limits, and range do you require?

• Determine the customers or consumers of the data and find out what levels of accuracy and detection they require. This will impact your QA/QC and calibration efforts as well as determine the specific sensors you will need.

How frequently do you need to collect data?

Automated monitoring has come a long way in the last decade and many automated platforms are cost-effective means of collecting environmental data. Not only do automated systems supply very high-resolution data, but they often require far less time and effort to maintain.

When designing a continuous monitoring system, you will need to determine how often to collect data samples.

• If not enough, you may miss important events.
• If too often, you may end up with heaps of unused data and a spent battery.

Download these examples for determining frequency of data collection in a presentation, complete with audio: Frequency Data Collection [PPSX in ZIP file, 731KB]

The sampling interval of a monitoring program is generally 15 minutes. However, this is not a rule. Sampling more frequently to start will help give you an understanding of the dynamics of the system. If readings tend to fluctuate significantly on a shorter time scale, then the monitoring interval can be adjusted to a shorter interval.

Keep in mind, though, that the more frequent the sampling interval, the more battery or power required. For sampling intervals less than 10 minutes, consider a solar panel and battery to preserve long deployment times.

Additionally, you can work with YSI's Integrated Systems & Services Team to define the best solution -- including sensors, electronics, telemetry, and platforms -- to meet your monitoring requirements.

systems@ysi.com
800-363-3269