{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp05_complete_proposal_portfolio20_20260803","cell_id":"layer_decay_and_expiration_management__environmental_climate","arm":"COMPLETE_PROPOSAL_PORTFOLIO","candidate_id":"stormwater-sediment-strata-lifecycle","proposal_index":5,"version":0,"title":"Expiration-Gated Management of Stormwater-Pond Sediment Strata","problem":"A stormwater pond receives successive sediment deposits carrying mineral particles, organic matter, litter, and particle-bound contaminants from different runoff periods. New deposits cover older strata while maintenance records usually describe the pond as one undifferentiated sediment volume. As the stack changes, some strata may consume needed detention or treatment capacity, while deeper material may remain important as an isolating layer, contain different contaminants, support established habitat, or preserve evidence of earlier watershed conditions. Dredging only when the pond appears full can mix these layers and remove material without testing what depends on it; leaving every stratum in place can allow capacity and maintenance obligations to accumulate unresolved.","actors":["Stormwater utility or pond owner","Drainage and pond-maintenance engineer","Sediment chemist or environmental laboratory","Aquatic ecologist","Dredging and dewatering contractor","Waste-classification and disposal authority","Environmental permitting regulator","Downstream community and ecological receptors"],"observable_state":"Bathymetry and available cores indicate sediment deposited in distinguishable depth bands or management cells, but the pond record does not consistently assign those deposits an estimated age, source period, volume, chemistry, ecological role, inspection date, dependency state, or disposition class. Maintenance decisions rely principally on total sediment depth, visible blockage, or elapsed time since the last dredging event.","consequence":"Undifferentiated accumulation can reduce usable pond volume and obscure where sediment management is actually required. A bulk cleanout may resuspend contaminants, breach a liner or isolating cap, destabilize banks, remove habitat, mix waste classes, or erase the stratigraphic record needed to interpret past loading. Indefinite deferral can leave progressively older deposits without an explicit decision or review date.","affected_objective":"Maintain the pond's authorized hydraulic and water-quality functions while preventing unmanaged sediment accumulation and avoiding removal that disregards contaminant boundaries, structural dependencies, habitat, or reconstruction evidence.","intervention":"Divide one pond into georeferenced sediment-management cells and establish a lifecycle register for their distinguishable depositional strata. For each stratum, record estimated deposition interval, depth, volume, source uncertainty, physical condition, available chemistry, hydraulic contribution, habitat observations, structural dependencies, review date, and state: active-capacity, review-due, characterization-required, retain-as-isolation, preservation-hold, removal-candidate, excavated-quarantine, or disposition-complete. Assign inspection TTLs at the cell and stratum class level; expiration prompts measurement and review rather than dredging. Rank review-due strata using age, capacity burden, contaminant concern, accessibility, uncertainty, ecological function, and reconstruction value, with permit, safety, liner, cap, and unresolved-contamination vetoes. Before excavation, require a dependency check covering bank stability, liners, utilities, contaminant isolation, habitat timing, downstream controls, and relationships among overlying and underlying strata. Authorized work proceeds by bounded cells rather than whole-pond default: retain, monitor, cap, isolate, pilot-dredge, or excavate to a specified boundary. Excavated material remains traceable in a controlled dewatering and characterization quarantine before final reuse, treatment, or disposal. The pond register retains the removed footprint, depth interval, evidence, and successor condition as a tombstone.","structural_mapping":[{"archetype_element":"Sequential deposits","domain_realization":"Runoff events and watershed changes deposit successive sediment strata within a stormwater pond."},{"archetype_element":"Layer inventory and identity","domain_realization":"Georeferenced cells and depth intervals give distinguishable sediment strata stable identities linked to observations and samples."},{"archetype_element":"Deposition order and age index","domain_realization":"Relative depth, maintenance history, and dated evidence establish an estimated sequence and uncertainty-bounded age for each stratum."},{"archetype_element":"Changed value or safe-retention status","domain_realization":"A stratum can shift from contributing useful substrate or isolation to consuming hydraulic capacity or presenting a management concern."},{"archetype_element":"Expiration trigger","domain_realization":"A class-specific inspection TTL, capacity threshold, observed erosion, or changed contaminant information triggers reassessment without automatically authorizing dredging."},{"archetype_element":"Layer value and risk comparison","domain_realization":"Review combines capacity burden, age, chemistry, accessibility, habitat role, structural role, uncertainty, and reconstruction value."},{"archetype_element":"Dependency check","domain_realization":"Pre-excavation review tests whether banks, liners, contaminant caps, habitat, utilities, downstream controls, or adjacent strata depend on the candidate layer."},{"archetype_element":"Differentiated disposition pathways","domain_realization":"A stratum may remain, receive monitoring, be capped or isolated, undergo a bounded pilot removal, be excavated into quarantine, or reach an approved final disposition."},{"archetype_element":"Preservation exception","domain_realization":"Named holds protect isolating strata, investigation evidence, habitat-sensitive cells, and layers with unresolved regulatory or structural dependencies."},{"archetype_element":"Reversible disposition stage","domain_realization":"Excavated sediment is held in controlled quarantine for additional characterization and routing before irreversible treatment, reuse, or disposal, although excavation itself is not represented as reversible."},{"archetype_element":"Deletion audit and tombstone","domain_realization":"After removal, the register preserves the former cell, depth interval, volume estimate, reason, approvals, destination, retained evidence, and resulting pond condition."},{"archetype_element":"Review and revalidation loop","domain_realization":"Retained strata, preservation holds, and characterization gaps receive new review dates instead of becoming silent permanent exceptions."}],"mechanism_mapping":[{"mechanism_slug":"stale_layer_detection_dashboard","role":"Maintains the cell-and-stratum inventory and surfaces elapsed inspections, unresolved identities, changing bathymetry, missing chemistry, conflicting records, and preservation holds due for revalidation.","counterfactual_removal":"Without a resolved inventory, the pond remains an undifferentiated sediment volume and managers cannot direct review toward specific aging or uncertain strata."},{"mechanism_slug":"time_to_live_ttl_policy","role":"Assigns each sediment class or management cell an inspection lifetime. Expiry changes the state to review-due or characterization-required and cannot initiate excavation.","counterfactual_removal":"Without a preassigned review trigger, strata are reassessed only after visible failure, generalized capacity pressure, or an unrelated maintenance event."},{"mechanism_slug":"age_weighted_value_score","role":"Orders review-due strata using age-weighted standing value together with capacity burden, contaminant concern, accessibility, habitat role, structural function, uncertainty, and reconstruction value. Veto conditions override the ranking.","counterfactual_removal":"Without a comparable triage input, investigation may focus on accessible or visibly deep areas while less obvious high-consequence strata remain unexamined."},{"mechanism_slug":"retention_schedule","role":"Maps sediment classes to measurement cadence, minimum evidence retention, permissible management routes, and regulatory, structural, ecological, or investigative holds.","counterfactual_removal":"Without class-level rules and named exceptions, similar strata receive inconsistent treatment and precautionary deferral can become indefinite."},{"mechanism_slug":"dependency_safe_delete_check","role":"Acts as a mandatory pre-excavation gate that traces physical and regulatory dependencies involving liners, caps, banks, utilities, habitats, adjacent strata, downstream controls, and permits.","counterfactual_removal":"Without this gate, a removal candidate can be excavated while still isolating contamination, supporting infrastructure, or protecting another layer from disturbance."},{"mechanism_slug":"soft_delete_quarantine_window","role":"Keeps excavated material identified and segregated in controlled dewatering quarantine while characterization and destination decisions remain reviewable. It makes final disposition reversible during the window but does not claim that excavation or lost stratigraphy can be undone.","counterfactual_removal":"Without the quarantine stage, uncertain or mixed sediment may be transported directly into an irreversible and potentially inappropriate reuse, treatment, or disposal route."},{"mechanism_slug":"tombstone_or_deletion_marker","role":"Leaves a durable geospatial and depth-specific record after excavation, identifying what was removed, its destination, retained evidence, and the cap, substrate, or successor condition now occupying the cell.","counterfactual_removal":"Without the marker, later surveys may interpret the altered depth profile as natural, repeat excavation across a protected boundary, or lose the chain connecting removed sediment to its characterization and destination."}],"causal_chain":["Runoff deposits sequential sediment layers whose sources, chemistry, and ecological context can differ over time.","Pond records aggregate the layers into total depth, so older strata remain unmanaged by default until generalized maintenance pressure arises.","Capacity concerns then favor broad dredging, while uncertainty about contamination, habitat, and structural dependencies favors indefinite delay.","The lifecycle register resolves the pond into identifiable cells and strata with age estimates, review dates, evidence, and explicit states.","TTL expiry and monitored changes generate a bounded characterization worklist rather than an automatic excavation order.","Value-and-risk ranking directs limited investigation, while dependency and veto checks protect liners, isolating layers, banks, habitat, permits, and downstream controls.","Authorized managers choose a stratum-specific path: retain, monitor, cap, isolate, pilot-dredge, or excavate to a defined boundary.","Excavated sediment remains segregated and traceable during dewatering and characterization so its final route can be corrected before irreversible disposition.","Tombstones preserve the removed interval and successor condition, allowing later maintenance and environmental interpretation to account for the intervention.","Repeated review bounds unresolved accumulation while retaining strata whose ecological, structural, regulatory, or evidentiary functions remain named."],"baseline":"The pond is inspected for visible condition and periodically surveyed for total sediment depth or remaining capacity. When a maintenance threshold is reached, managers scope a partial or whole-pond dredging project and characterize excavated material for handling. Historical strata may be inferred during design, but they do not consistently receive persistent lifecycle identities, individual review triggers, dependency states, preservation holds, quarantine status, or post-removal tombstones.","nearest_rivals":["Whole-pond dredging on a fixed calendar.","Dredging triggered solely by a total-volume or minimum-depth threshold.","Waste characterization performed only after sediment has been excavated and mixed.","Installing or enlarging a forebay to simplify future sediment removal.","Upstream erosion and source controls intended to reduce future deposition.","Routine bathymetric monitoring that measures accumulation but does not govern stratum-specific retention or disposition.","Permanent no-dredge management intended to avoid contaminant disturbance."],"remaining_contrastive_claim":"The proposal treats pond sediment as sequential, heterogeneous, dependency-bearing strata rather than one bulk maintenance volume. Its causal contribution is the coupling of stratum identities, expiration-to-characterization, ranked review, pre-excavation dependency gates, bounded-cell disposition, controlled material quarantine, and depth-specific tombstones. It is not merely bathymetric monitoring, fixed-threshold dredging, waste testing, or source control.","authority_safety":{"decision_authority":"The pond owner or stormwater utility may commission inventory and engineering review. A qualified engineer and environmental professional define candidate management boundaries. Excavation, capping, reuse, treatment, or disposal requires the owner's authorization plus applicable environmental, waste, habitat, safety, and permitting approvals.","authorized_first_step":"For one pond, reconcile existing design drawings, maintenance records, prior analyses, and non-disturbing bathymetric or surface observations into a provisional cell-and-stratum inventory. No coring, excavation, dewatering, treatment, transport, or lifecycle-state change to the pond is authorized.","excluded_actions":["Using TTL expiry or a score as authority to dredge","Assuming depth or age establishes contaminant status","Coring, excavating, breaching, mixing, capping, or moving sediment during the inventory-only step","Disturbing a liner, isolating cap, bank, utility, protected habitat, or unknown submerged structure","Combining excavated cells before their identity and characterization requirements are resolved","Sending sediment to reuse, treatment, or disposal without required characterization and approval","Representing dewatering quarantine as capable of restoring excavated stratigraphy","Overriding access restrictions, water-safety procedures, habitat timing, waste rules, or permit conditions","Publishing restricted infrastructure or contamination-location information without authorization"],"halt_rollback":"Stop survey work if access is unsafe, bathymetric equipment could contact a liner or structure, protected wildlife or habitat could be disturbed, an unexpected discharge is observed, or records reveal an unrecognized contamination or permit constraint. Withdraw equipment without disturbing sediment, preserve original records and provisional observations, and refer the issue to the pond owner and qualified authorities. Because the first step makes no physical change, rollback removes provisional classifications while retaining the audit record and uncertainty flags."},"negative_tests":{"strongest_counterevidence":"The bounded pond retains its required hydraulic capacity, available evidence shows no management-relevant stratigraphic or contaminant differentiation, all sediment areas already have explicit inspection and disposition states, and existing maintenance controls account for liners, habitat, permits, and historical evidence before any removal.","problem_falsifier":"Records and non-disturbing observations show no unresolved sequential accumulation: the pond contains either negligible deposited sediment or one intentionally managed homogeneous layer, with current capacity, complete maintenance history, and no ambiguous retention or dependency decision.","intervention_falsifier":"Available observations and proportionate sampling cannot resolve strata or management cells at a scale that supports different actions, reviewer classifications are not reproducible, or dependency constraints make every proposed state collapse into the same whole-pond management decision.","risks":["Bathymetry may suggest boundaries that chemical or physical sampling does not confirm.","Age and source estimates may be too uncertain to support stratum-specific decisions.","Composite scoring can create false precision around ecological and contaminant tradeoffs.","Later coring or dredging can resuspend contaminants or penetrate a liner or isolating layer.","Cell-by-cell excavation can still mix strata at boundaries or during dewatering.","Quarantine runoff, dust, or equipment contact can create new exposure pathways.","Retained reference samples may not represent spatial heterogeneity in the removed material.","Habitat observations made during one season may misstate year-round dependency.","Preservation holds may accumulate and prevent the active stack from becoming bounded.","The register may become stale as new sediment rapidly alters surveyed surfaces.","Optimizing hydraulic capacity may overshadow downstream, habitat, or environmental-justice concerns." ]},"next_evidence_step":"For one selected pond, compare existing design elevations and maintenance records with a non-disturbing bathymetric survey to estimate deposited volume, spatial heterogeneity, and candidate management cells. Reconcile any existing sediment analyses or cores to those cells and have two qualified reviewers independently assign provisional lifecycle states, uncertainty, dependency questions, and proposed review priorities. Determine whether the available evidence supports distinct stratum-level decisions and specify the smallest separately authorized sampling plan needed to test unresolved boundaries. No sediment is disturbed or removed in this step.","prior_art_status":"UNSEARCHED","diversity_from_prior_proposals":"Proposal 1 manages installed erosion-control mats whose removal can destabilize vegetation and banks. This proposal instead manages sediment naturally deposited into a stormwater treatment asset, with hydraulic capacity, contaminant stratigraphy, liners, and bounded dredging as its central constraints. Proposal 2 governs the authority and archival status of digital climate-hazard map editions; this proposal changes how in-situ material strata are characterized and physically retained or excavated. Proposal 3 governs laboratory-held environmental specimens; although this proposal may use cores as evidence, the lifecycle target is the pond's full in-situ sediment stack and its hydraulic and contaminant functions, not the custody or freezer disposition of samples. Proposal 4 governs executable drought-operation rule patches; this proposal governs deposited matter through field measurement, dependency-gated excavation, dewatering quarantine, and material disposition. It is independently adoptable as a pond-maintenance regime and is not a feature or population variant of any earlier proposal.","revision_record":{"parent_version":null,"progress_targets_addressed":[],"conceptual_changes":[],"operational_changes":[],"evidence_changes":[],"claim_changes":[]}}