RMP.4:5.1 - ResidentStream-S17: preserve a useful trace after losing the comparison
The selected design would compare salinity-related observations at a downstream reach and a reference reach during an informative thaw event. Assume the measurement method, calibration basis, safe access and intended site-period relation were qualified when the design was chosen.
During the event, downstream observations are made, but the reference reach becomes inaccessible. The team retains the following linked account:
| Retained material | What the account says and permits |
|---|---|
| The selected design and the plan that existed before the event | The intended examination was a paired site-period comparison, not downstream trend description alone. |
| Downstream sample and measurement records | Sample IDs connect time, reach, hydrological context, instrument indications and the qualified measurement results, including the relevant uncertainty. |
| The reference-visit record | The visit was not performed for the named period because access failed. The account identifies the source supporting that reason; it contains no invented reference value. |
| Preparation of a later chart | The transformation connects each displayed downstream value to its measurement record and marks the absent comparison. A chart containing only downstream values cannot silently retain the paired-comparison claim. |
| The changed research-use account | RMP.2 receives the lost comparison premise. The retained observations remain available for a separately justified narrower use. |
Two examinations now differ. A reader can inspect the downstream measurement and handling history. The same reader cannot perform the original paired thaw-event comparison because the reference observation does not exist. Keeping all the surviving files does not remove that difference.
A reference sample taken later in dry weather is new material under different hydrological conditions. Its use requires a justified comparability premise, not a change of file name or a routine replacement of the blank cell.
Suppose volunteers began sampling before any protocol was recorded. The team can reconstruct part of their procedure from contemporaneous sample labels, instrument logs and later reports. The reconstruction names those bases and their uncertainty. It is dated when reconstructed and does not claim that all choices were prospectively fixed.
Private land-access details can remain controlled under the actual permissions. The public account identifies the omitted material’s research role and the examinations possible without it. It promises neither the lost event nor unrestricted independent inspection.