[Content] Add the Concentrated Leak Erosion Freezing Screening technical reference manual to the System Response Library

docs/web-applications/system-response/cle-freezing-screening/v1.0/00-document-info.mdx

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+---
+title: Document Info
+reportDate: October 2026
+reportType: Technical Reference
+reportTitle: Concentrated Leak Erosion Freezing Screening Technical Reference Manual
+reportSubTitle: System Response Library
+reportAuthors: ['Adam Gohs, P.E.']
+reportAbstract: Technical reference documenting the concentrated leak erosion (CLE) freezing screening model in the System Response library. The model computes a system response probability (SRP) at each headwater level for concentrated leak erosion through a transverse crack opened at the crest of an embankment by freezing. The probability of a continuous frost crack is scored by risk-factor and likelihood-factor weighting of three site factors — the freeze-duration climate, the soils the crack crosses at the crest, and the surface cover over the core — and an observation of continuous frost cracking overrides it to certainty. The crack depth is taken from the climate, and initiation is certain once the pool rises above the bottom of the crack. The remaining nodes of the eight-node CLE event tree follow the methods shared by the CLE screening family. The model is fully deterministic apart from any Monte Carlo filter evaluation in the continuation node, and applies simplifications appropriate for screening-level risk analysis.
+reportSubjectTerms: ['CLE', 'Concentrated Leak Erosion', 'Frost Cracking', 'Freezing', 'Transverse Cracking', 'Crest Crack', 'Screening', 'Event Tree', 'System Response Probability', 'System Response Curve', 'Risk Factor', 'Likelihood Factor']
+citationGuide: 'U.S. Army Corps of Engineers, Risk Management Center, <i>Concentrated Leak Erosion Freezing Screening Technical Reference Manual</i>, Lakewood, CO: U.S. Army Corps of Engineers, Risk Management Center, 2026.'
+---
+
+import Link from '@docusaurus/Link';
+import DocumentMetadata from '@site/src/components/DocumentMetadata';
+import NavContainer from '@site/src/components/NavContainer';
+
+<NavContainer
+  link="/web-applications/system-response"
+  linkTitle="System Response Library"
+  document="web-applications/system-response/cle-freezing-screening"
+/>
+
+# Document Information
+
+<DocumentMetadata metadata={frontMatter} />

docs/web-applications/system-response/cle-freezing-screening/v1.0/00-version-history.mdx

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+---
+title: Version History
+---
+
+import NavContainer from '@site/src/components/NavContainer';
+import TableVersionHistory from '@site/src/components/TableVersionHistory';
+
+<NavContainer
+  link="/web-applications/system-response"
+  linkTitle="System Response Library"
+  document="web-applications/system-response/cle-freezing-screening"
+/>
+
+# Version History
+
+<TableVersionHistory
+  versions={['1.0']}
+  dates={['October 2026']}
+  descriptions={['Initial release as an online document.']}
+  modifiedBy={['-']}
+  reviewedBy={['-']}
+  approvedBy={['-']}
+/>

docs/web-applications/system-response/cle-freezing-screening/v1.0/01-preface.mdx

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+---
+title: Preface
+---
+
+import NavContainer from '@site/src/components/NavContainer';
+
+<NavContainer link="/web-applications/system-response" linkTitle="System Response Library" document="web-applications/system-response/cle-freezing-screening" />
+
+# Preface
+
+This document provides a technical reference for the concentrated leak erosion (CLE) freezing screening model in the System Response library. The
+model computes a system response probability (SRP) as a function of headwater elevation for concentrated leak erosion through a transverse crack
+opened at the crest of an embankment by freezing (frost cracking). It is a screening-level model: it applies simplifications intended to reduce
+input burden while avoiding false negatives, and any application that performs screening-level risk analysis can use it.
+
+The model is one of eight CLE screening models that share one event tree, one flaw-scoring scheme, one initiation treatment for crest cracks, and
+one set of failure-pathway rules. Those shared methods are documented once, in the
+[Concentrated Leak Erosion Common Methods Screening Technical Reference Manual](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/preface),
+and the continuation node is evaluated by the shared method documented in the
+[Continuation (Filter Evaluation) Screening Technical Reference Manual](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/preface).
+This document covers what is specific to frost cracking — the flaw assessment, the crack depth that sets where initiation can begin, the
+mechanism-specific inputs, and the assumptions that come with them — and links the chapter of the shared manuals that documents each common step.
+
+The intended audience includes dam safety engineers evaluating whether the model is appropriate for their assessment, and peer reviewers checking
+the technical basis of screening-level results. Readers are assumed to have a general background in internal-erosion risk analysis — event trees,
+concentrated leak erosion mechanics, and probability concepts — but no familiarity with the software implementation is required.
+
+## Document Organization
+
+- **[Model Overview](./02-model-overview.mdx)** — The model's purpose and intended use, a summary of its execution pathway from inputs to
+  results, its physics basis, a comparison with detailed analysis, and its relationship to the shared CLE and continuation methods.
+- **[Input Parameters](./03-input-parameters.mdx)** — The mechanism-specific inputs (the freeze-duration climate, the crest soils, the surface
+  cover over the core, and the observation of continuous frost cracking), and how this model uses each group of inputs shared with the CLE
+  family.
+- **[Flaw Assessment](./04-flaw-assessment.mdx)** — The risk-factor and likelihood-factor scoring of the three site factors, the weighted-sum
+  curve and its lower threshold, the observation override, the treatment of crest soils that cannot frost-crack, and the crack depth, bottom of
+  the crack, and crack width.
+- **[Event Tree](./05-event-tree.mdx)** — How this model populates each of the eight CLE event-tree nodes at each pool level, how the SRP is
+  computed, and a worked example.
+- **[Assumptions and Limitations](./06-assumptions-and-limitations.mdx)** — Each assumption specific to this model with its engineering basis, its
+  effect on results, and the conditions under which it may not hold.
+- **[Output and Interpretation](./07-output-and-interpretation.mdx)** — The results the model produces, how to read the system response curve and
+  the flaw-assessment results, and the role of screening results relative to detailed analysis.

docs/web-applications/system-response/cle-freezing-screening/v1.0/02-model-overview.mdx

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+---
+title: Model Overview
+---
+
+import Citation from '@site/src/components/Citation';
+import CitationFootnote from '@site/src/components/CitationFootnote';
+import NavContainer from '@site/src/components/NavContainer';
+import TableReference from '@site/src/components/TableReference';
+import TableVertical from '@site/src/components/TableVertical';
+
+<NavContainer link="/web-applications/system-response" linkTitle="System Response Library" document="web-applications/system-response/cle-freezing-screening" />
+
+# Model Overview
+
+## Purpose
+
+The CLE freezing screening model computes a system response curve for concentrated leak erosion through a frost crack at the crest of an
+embankment, as a function of headwater elevation. The system response probability (SRP) at each headwater level is the conditional probability of
+breach of the embankment by concentrated leak erosion through such a crack, given that pool level.
+
+The flaw is a transverse crack — one running across the crest, from the upstream to the downstream side — opened in the crest soils by freezing. It
+is open at the crest and extends down to a bottom-of-crack elevation set by the depth of cracking. When the pool rises above the bottom of the crack,
+water can flow through it, erode its walls, and enlarge it into a concentrated leak.
+
+:::warning[INPUT NEEDED IN-01 — Definition]
+The physical mechanism by which freezing opens a transverse crack at the crest is not described, and neither is the reason each of the model's
+three site factors bears on it: why a longer freeze duration, a crest soil of a given classification, and the surface cover over the core
+(paved, gravel road, or no road or pathway) make a continuous frost crack more or less likely. State the mechanism and the direction of each factor
+so that it can be described here, with a literature source where one applies.
+
+Proposed (unconfirmed): freezing of the crest soils causes contraction and ice segregation that open transverse cracks, which deepen and widen
+with the duration of freezing; fine-grained soils are the most susceptible, and a surface cover that is kept clear of snow, such as a paved road,
+changes the insulation of the crest and so the cracking. Confirm, correct, or replace — in particular the direction of the surface-cover factor,
+under which a paved crest scores as the least likely condition.
+:::
+
+## Intended Use
+
+The model is a screening-level assessment of the risk of concentrated leak erosion through a frost crack. It makes simplifying and generally
+conservative assumptions with two goals:
+
+- **Preventing false negatives** — The model aims to avoid underestimating risk at the screening level, so that embankments with a
+  potential frost-cracking concern are flagged for further analysis. This is a goal rather than a guarantee: the score of an Unknown crest soil is
+  not the most conservative choice, and a weighted sum below 13 gives a zero raw flaw probability (Assumptions 3 and 4 in
+  [Assumptions and Limitations](./06-assumptions-and-limitations.mdx#flaw-assessment)). Initiation is taken as certain once water can enter the crack, and the most
+  crack-susceptible of the crest soils governs the flaw assessment.
+- **Reducing input burden** — Three qualitative selections — a freeze-duration climate category, the soil classifications at the crest, and the
+  surface cover over the core — substitute for site-specific measurements of frost penetration and crack geometry. The crack depth follows from
+  the climate category alone.
+
+The model is not intended for detailed or semi-quantitative risk assessments. For higher-level analyses, the internal-erosion probability methods of
+Fell et al. (2024) <Citation citationKey="Fell2024" /> and the crack-geometry initiation analyses of the Concentrated Leak Erosion Initiation
+toolbox provide the complete methodologies (see [Comparison with Detailed Models](#comparison-with-detailed-models)).
+
+## How the Model Works
+
+The model executes the three stages common to the CLE screening family (see the
+[Model Overview](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/model-overview#how-the-model-works) of the common
+methods manual):
+
+1. **Flaw assessment** — The model scores the freeze-duration climate, the most crack-susceptible soil the crack crosses at the crest, and the
+   surface cover over the core with risk-factor and likelihood-factor weighting, and converts the weighted sum to the probability of a continuous
+   frost crack. An observation of continuous frost cracking overrides the score to certainty. The climate category also sets the crack depth, and
+   the bottom of the crack is the crest elevation less that depth. When every listed crest soil is one that cannot frost-crack, the mechanism does
+   not apply and no crack forms (see [Flaw Assessment](./04-flaw-assessment.mdx)).
+
+2. **Pathway resolution** — The model takes the failure pathway as supplied: the top of the first filter the crack meets, if any, the filter and
+   base-soil description, the soils that must hold a roof over the enlarging pipe below and above the filter's top, the embankment type, and the
+   upstream seepage-limiting elements with the top of any wall (see [Input Parameters](./03-input-parameters.mdx#inputs-shared-with-the-cle-family)).
+
+3. **Event-tree assembly** — At each headwater level, the model composes the eight CLE event-tree node probabilities and multiplies them to produce
+   the SRP. Initiation is zero at or below the bottom of the crack and certain above it; continuation, roof support, and flow limitation are each
+   evaluated for the pathway that governs at that pool level (see [Event Tree](./05-event-tree.mdx)).
+
+Every node is deterministic except continuation, which the shared continuation method evaluates by Monte Carlo simulation when it assesses a
+filter from the soil classifications of the base and filter soils.
+
+## Physics Basis
+
+The model combines the following engineering methods:
+
+- **Risk-factor and likelihood-factor scoring** of the probability of a continuous flaw, in which each site factor receives a likelihood factor
+  weighted by a risk factor and the weighted sum is mapped to a probability <Citation citationKey="Fell2024" />, as documented for the CLE family
+  in [Flaw Conventions](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#risk-factor-and-likelihood-factor-scoring)
+- **A climate-dependent crack depth** that places the bottom of the frost crack below the crest (see
+  [Flaw Assessment](./04-flaw-assessment.mdx#crack-depth-and-bottom-of-the-crack))
+- **A headwater gate at the bottom of the open crack** for initiation, as documented for the crest-crack models in
+  [Initiation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#crest-crack-models-headwater-gate)
+- **Filter evaluation, roof-support, crack-filling, and flow-limitation probabilities** for continuation and progression, applied through the
+  crest-crack pathway rules documented in
+  [Failure Pathway and Progression](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression)
+
+## Comparison with Detailed Models
+
+In a detailed risk analysis, the probability of a frost crack, its depth and width, and the likelihood that erosion initiates in it are assessed by
+the risk team from the site evidence, informed by the internal-erosion probability methods of Fell et al. (2024) <Citation citationKey="Fell2024" />.
+The initiation of erosion in a crack of known geometry can be evaluated with the
+[Vertical Rectangular Crack](/docs/toolbox-technical-manuals/internal-erosion-suite/concentrated-leak-erosion-initiation/v1.0/vertical-rectangular-crack)
+and [Vertical Triangular Crack](/docs/toolbox-technical-manuals/internal-erosion-suite/concentrated-leak-erosion-initiation/v1.0/vertical-triangular-crack)
+analyses of the Concentrated Leak Erosion Initiation toolbox, which compare the hydraulic shear stress in the crack with the critical shear stress
+of its walls. <TableReference tableKey="cle-freezing-screening-table-1" /> summarizes the differences.
+
+<TableVertical
+  tableKey="cle-freezing-screening-table-1"
+  alt="Comparison of the CLE freezing screening model and detailed analysis"
+  caption="Comparison of the CLE freezing screening model and detailed analysis."
+  headers={[[{ value: 'Aspect' }, { value: 'Screening Model' }, { value: 'Detailed Analysis' }]]}
+  columns={[
+    ['Purpose', 'Flaw probability', 'Crack depth', 'Crack width', 'Initiation', 'Progression'],
+    [
+      'Screening-level risk assessment',
+      'Scored from climate, crest soil, and surface cover; observation override',
+      'Tabulated by freeze-duration climate category',
+      'Reported for reference; not used in the event tree',
+      'Certain once the pool rises above the bottom of the crack',
+      'Tabulated roof-support, crack-filling, and flow-limitation probabilities',
+    ],
+    [
+      'Detailed risk analysis',
+      'Estimated by the risk team from the totality of the evidence',
+      'Estimated by the analyst for the site',
+      'An input to the crack-geometry initiation analysis',
+      'Shear stress analysis of the crack geometry',
+      'Assessed by the risk team, informed by the same tables',
+    ],
+  ]}
+/>
+
+## Relationship to the Shared Methods
+
+The model is one of the four crest-crack models of the CLE screening family (see
+[The Two Model Groups](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/model-overview#the-two-model-groups) in the
+common methods manual). Everything after the flaw assessment is common to those models: the event-tree structure, the headwater gate for
+initiation, the crest-crack pathway rules for continuation and roof support, the crack-filling and flow-limitation tables, and the form of the
+results. This manual documents the frost-cracking flaw assessment in full and, for every other node, states what this model supplies and links the
+chapter of the common methods manual that documents the method. The continuation node hands the filter evaluation to the shared continuation method,
+which combines its results across the base soils the filter protects as described in
+[Method Selection and Governing Base Soil](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/method-selection-and-governing-base-soil).
+The model uses no toolbox method.
+
+The closest sibling is the desiccation screening model, which shares the structure of the flaw assessment — three factors, a weighted-sum
+threshold of 13, an observation override, and a set of crest soils in which the mechanism cannot occur. It also scores the climate and the crest
+soil, but on its own tables and with its factors weighted differently: its surface layer carries a risk factor of 3, its climate 2, and its crest
+soil 1.
+
+<CitationFootnote />