Well purges
A Well Purge records a single event in which standing water is removed from a Well before a groundwater Sample is collected. It captures how the purge was run — the method, the stop criterion, the volume and rate removed, and the field outcome — so the purge that preceded a sample is part of the record, not lost in a field notebook.
A Well Purge belongs to a Site and a Project, and is recorded at a Location — the point on the Site that was purged — optionally naming the specific Well. As with the site's other field-monitoring records, the Location is the measurement point, not the scope it lives under.
When a purge record exists
A Well Purge row exists only when water was actually purged. Passive or no-purge sampling — diffusion bags, HydraSleeve, Snap Samplers — never creates a Well Purge; that is a property of the sample, not a purge event.
Well Purges cover the standard pre-sampling protocols: low-flow micropurge, conventional volume-based purging, and low-yield purge-and-recover. They do not cover aquifer or pumping tests. Static groundwater gauging belongs to Water Levels instead.
What a purge records
A purge captures the strategy, the timing, and the measured outcome. The Method describes the purge strategy; the physical device used (a specific bladder pump, for example) is recorded separately as equipment, not as the method. The Criterion records why purging was judged complete.
| Field | Type | Required | Description |
|---|---|---|---|
| Location | reference | Yes | The point being purged |
| Project | reference | Yes | The owning Project |
| Well | reference | No | The specific Well purged, if recorded |
| Method | enum | No | Purge strategy — see below |
| Criterion | enum | No | Stop reason — see below |
| Equipment | reference | No | The device used (pump, bailer) |
| Purge Start | date/time | Yes | When purging began |
| Purge End | date/time | No | When purging ended — cannot precede the start |
| Target Volume | number | No | Intended volume; shares the volume unit |
| Purged Volume | number | No | Volume actually removed (0 allowed — dry on arrival) |
| Volume Unit | enum | Conditional | Required when a target or purged volume is set |
| Purge Rate | number | No | Flow rate during purging |
| Purge Rate Unit | enum | Conditional | Required when a purge rate is set |
| Pump Depth | number | No | Intake depth (0 allowed) |
| Pump Depth Unit | enum | Conditional | Required when a pump depth is set |
| Dry | yes/no | No | The well ran dry during purging (default No) |
| Valid | yes/no | No | Whether the record is valid (default Yes) |
| Qualifier | text | No | Short data qualifier (up to 100 characters) |
| Purged By | text | No | Who performed the purge (up to 200 characters) |
| Notes | text | No | Free-text notes (up to 1000 characters) |
A record with no measurements at all — no volume, rate, pump depth, or end time — and not marked Dry must carry a Qualifier or Notes explaining why, otherwise the save is rejected. Each value-and-unit pair is enforced together: a volume needs a volume unit, a rate needs a purge rate unit, and a pump depth needs a pump-depth unit.
A future-dated Purge Start is allowed but raises a warning. Warnings do not block the save; they surface after a successful save so you can confirm the entry.
Method
The purge strategy. Wire value is the Code (same as the name shown below).
| Value | Code | Meaning |
|---|---|---|
| Low-Flow (Micropurge) | LowFlow | Minimal-drawdown purge, governed by parameter stabilization |
| Conventional (Volume-Based) | ConventionalVolume | Volume-averaged purge, typically several casing volumes |
| Low-Yield (Purge & Recover) | LowYield | Purge to dryness, let the well recover, then sample |
| Other | Other | Any other strategy |
Criterion
The basis on which purging was judged complete — the stop reason. Wire value is the Code.
| Value | Code | Meaning |
|---|---|---|
| Parameter Stabilization | Stabilization | Field parameters settled within criteria |
| Casing Volumes | CasingVolumes | A computed multiple of casing volume was removed |
| Fixed Volume | FixedVolume | A flat target volume, regardless of casing geometry |
| Fixed Duration | FixedDuration | Purged for a set time |
| Purged to Dryness | PurgedDry | Stopped because the well evacuated |
| Other | Other | Any other basis |
Recording a dry well
A well that runs dry is recorded along up to three independent axes that can coexist on one record:
- Dry — the physical outcome, possibly unintended.
- Criterion = Purged to Dryness — the stop reason.
- Method = Low-Yield (Purge & Recover) — the intended strategy.
How it fits together
A Well Purge sits between the field readings that describe stabilization and the Sample that follows. It shares its Location and timing with the Field Parameters measured during purging, but there is no stored link between them in V1 — they are correlated by Location and time. The closely related Water Level record covers static gauging, a separate event from purging.
Figure: a Well Purge belongs to a Location and may name a Well. The Field Parameters taken while purging share the Location and timing but are not linked by a stored relationship in V1.
| Aspect | Well Purge | Water Level |
|---|---|---|
| Records | Water removed before sampling | Static groundwater gauging |
| Exists when | Water was actually purged | Any routine gauging reading |
| Captures | Volume, rate, method, criterion | Depth to water, elevations, free product (NAPL) |
Delete several at once
The Well Purges grid supports multi-select deletion. Tick the checkbox on each row you want (or use the header checkbox to select the whole page), then select Delete selected (N) above the grid and confirm. This grid loads a page at a time, so selection covers the current page — to remove a larger set, narrow it with a filter first. Search, filter, sort, and Export apply to the whole table; see Working with data grids.
Bulk deletion is permanent and cannot be undone. Each removed well purge is recorded individually in the Audit Log. Bulk delete is unavailable while the Site is locked.