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

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

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+---
+title: Document Info
+reportDate: October 2026
+reportType: Technical Reference
+reportTitle: Concentrated Leak Erosion Desiccation Screening Technical Reference Manual
+reportSubTitle: System Response Library
+reportAuthors: ['Adam Gohs, P.E.']
+reportAbstract: Technical reference documenting the concentrated leak erosion (CLE) desiccation 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 formed by desiccation (drying and shrinkage) of the soil at the embankment crest. The probability that a continuous desiccation crack exists is scored from three site factors — the surface layer over the core, the climate or the measured net evaporation, and the plasticity of the crest soils — using risk-factor and likelihood-factor scoring. The depth of the crack is taken from tabulated values by climate, soil, and surface layer, and the bottom of the crack sets the pool level above which concentrated leak erosion can begin. The remaining nodes of the eight-node event tree follow the methods shared by the CLE screening models. The model is deterministic, except that the shared continuation method may estimate the continuation node by sampling, and it applies simplifications appropriate for screening-level risk analysis.
+reportSubjectTerms: ['CLE', 'Concentrated Leak Erosion', 'Desiccation Cracking', 'Crest Cracking', 'Screening', 'Event Tree', 'System Response Probability', 'System Response Curve', 'Risk Factor', 'Likelihood Factor', 'Net Evaporation', 'Crack Depth']
+citationGuide: 'U.S. Army Corps of Engineers, Risk Management Center, <i>Concentrated Leak Erosion Desiccation 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-desiccation-screening"
+/>
+
+# Document Information
+
+<DocumentMetadata metadata={frontMatter} />

docs/web-applications/system-response/cle-desiccation-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-desiccation-screening"
+/>
+
+# Version History
+
+<TableVersionHistory
+  versions={['1.0']}
+  dates={['October 2026']}
+  descriptions={['Initial release.']}
+  modifiedBy={['-']}
+  reviewedBy={['-']}
+  approvedBy={['-']}
+/>

docs/web-applications/system-response/cle-desiccation-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-desiccation-screening" />
+
+# Preface
+
+This document provides a technical reference for the concentrated leak erosion (CLE) desiccation 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 that forms when the soil at the embankment crest dries and shrinks. 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 desiccation model is one of eight CLE screening models. The eight share an event-tree structure, an
+initiation treatment for cracks open at the crest, failure-pathway rules for the continuation and progression nodes, and the form of their results,
+and seven of the eight, this model among them, share a scoring scheme for flaw probabilities.
+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 desiccation cracking: the site factors scored for the probability of a continuous crack, the tabulated
+crack depth and the bottom-of-crack elevation that follows from it, the observation that overrides the scored probability, the soils in which the
+mechanism does not apply, and how the shared nodes are populated for this mechanism. Each section links the chapter of the shared manuals that
+documents the common method it relies on.
+
+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 engineering basis, a comparison with a detailed assessment, and its place among the CLE screening models.
+- **[Input Parameters](./03-input-parameters.mdx)** — The desiccation-specific inputs — the surface layer over the core, the climate, the measured
+  net evaporation, the crest soils, and the cracking observation — and a summary of the inputs shared with the other CLE models.
+- **[Flaw Probability](./04-flaw-probability.mdx)** — The three scored factors, their likelihood factors, the weighted sum, the curve that converts
+  it to a flaw probability, the lower threshold, the observation override, and the inapplicable-mechanism case.
+- **[Crack Depth](./05-crack-depth.mdx)** — The tabulated crack depths by climate, soil, and surface layer, their interpolation by measured net
+  evaporation, and the bottom-of-crack elevation passed to the downstream nodes.
+- **[Event Tree](./06-event-tree.mdx)** — How each of the eight event-tree nodes is populated for desiccation cracking at each pool level, and how
+  the SRP is computed.
+- **[Assumptions and Limitations](./07-assumptions-and-limitations.mdx)** — Each desiccation-specific modeling assumption with its engineering
+  basis, its effect on results, and the conditions under which it may not hold.
+- **[Output and Interpretation](./08-output-and-interpretation.mdx)** — The flaw-assessment results the model reports, how to read the system
+  response curve for this mechanism, and the role of screening results relative to detailed analysis.

docs/web-applications/system-response/cle-desiccation-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-desiccation-screening" />
+
+# Model Overview
+
+## Purpose
+
+The CLE desiccation screening model computes a system response curve for concentrated leak erosion through a desiccation crack at the embankment
+crest, 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.
+
+Desiccation cracking is the opening of cracks in the soil near the crest as it dries and shrinks. Where a desiccation crack runs transversely
+across the crest and is continuous from the upstream face to the downstream face, it opens a path through the embankment from the crest down to
+the bottom of the crack. When the pool rises above the bottom of the crack, water flows through it and can erode its walls. The failure mode then
+proceeds as for any concentrated leak: the erosion must find an unfiltered exit, the enlarging pipe must stay open and be neither filled nor starved
+of flow, intervention must fail, and an uncontrolled release of the impounded water must follow.
+
+## Intended Use
+
+The model is a screening-level assessment of concentrated leak erosion through desiccation cracking at the crest. Like the other CLE screening
+models, it makes simplifying and generally conservative assumptions with two goals
+(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#intended-use) of the CLE
+Common Methods manual):
+
+- **Preventing false negatives** — The model is designed to avoid underestimating risk at the screening level, so that embankments with a
+  potential desiccation-cracking concern are flagged for further analysis.
+- **Reducing input burden** — Three qualitative site descriptions — the surface layer over the core, the climate, and the soil classes at the crest
+  — stand in for an assessment of crack occurrence and crack depth from site investigation. A measured average annual net evaporation may replace
+  the climate description where it is available.
+
+The model is not intended for detailed or semi-quantitative risk assessments (see
+[Comparison with Detailed Models](#comparison-with-detailed-models)).
+
+## How the Model Works
+
+The model executes the three stages common to the CLE screening models
+(see [How the Model Works](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) in the CLE
+Common Methods manual), with a desiccation-specific flaw assessment:
+
+1. **Flaw assessment** — The model scores three site factors on a likelihood scale of 1 to 4: the surface layer over the core, the climate (or
+   the measured net evaporation), and the plasticity of the soils the crack would cross. The weighted sum of the scores is converted to the
+   probability that a continuous desiccation crack exists. A weighted sum below 13 gives a zero probability, and a report that continuous transverse
+   cracking caused by desiccation has been observed sets the probability to 1.0 (see [Flaw Probability](./04-flaw-probability.mdx)). From the same
+   descriptions the model takes a tabulated crack depth and computes the bottom-of-crack elevation (see [Crack Depth](./05-crack-depth.mdx)).
+
+2. **Pathway resolution** — From the user's description of the embankment along the crack, the model takes the top of the first filter the
+   failure pathway meets, the soils along the pathway, the embankment type, and the upstream seepage-limiting elements, following the conventions
+   for cracks open at the crest
+   (see [The Failure Pathway](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression#the-failure-pathway)
+   in the CLE Common Methods manual).
+
+3. **Event-tree assembly** — At each headwater level the model multiplies the eight node probabilities. When the mechanism applies, initiation is
+   certain once the pool rises above the bottom of the crack and zero at or below it; when every listed crest soil is a clean or nearly clean sand
+   or gravel, it is zero at every pool level; continuation, roof support, and flow limitation follow the pool level relative to the top
+   of the filter and the top of any upstream wall (see [Event Tree](./06-event-tree.mdx)).
+
+Every node is evaluated directly from the inputs and tabulated values. The model performs no Monte Carlo simulation of its own; the continuation
+node is the only one that may be a Monte Carlo estimate, when the shared continuation method evaluates the filter by sampling
+(see [Event Tree](./06-event-tree.mdx#node-3-continuation)).
+
+## Physics Basis
+
+The model combines the following engineering methods:
+
+- **Risk-factor and likelihood-factor scoring** for the probability of a continuous flaw, in which each site factor is assigned a likelihood
+  factor, weighted by a risk factor, and the weighted sum is mapped to a flaw probability <Citation citationKey="Fell2024" /> (see
+  [Risk-Factor and Likelihood-Factor Scoring](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)
+  in the CLE Common Methods manual). The desiccation factors express that a crack is more likely where the crest is unprotected, the climate is
+  drier, and the soil is more plastic (see [Flaw Probability](./04-flaw-probability.mdx)).
+- **Tabulated desiccation crack depths** by climate, soil, and surface layer, adapted from Fell et al. (2024) <Citation citationKey="Fell2024" />
+  (see [Crack Depth](./05-crack-depth.mdx)).
+- **The headwater gate at the bottom of an open crest crack** for initiation, as documented in
+  [Crest-Crack Models: Headwater Gate](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)
+  in the CLE Common Methods manual.
+- **Tabulated roof-support, crack-filling, and flow-limitation probabilities** for the progression nodes <Citation citationKey="Fell2024" />, and
+  **filter evaluation** for the continuation node through the shared continuation method, both applied as 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) in
+  the CLE Common Methods manual.
+
+## Comparison with Detailed Models
+
+The detailed counterpart of the screening model is an assessment of desiccation cracking and concentrated leak erosion by the internal-erosion
+probability methods of Fell et al. (2024) <Citation citationKey="Fell2024" /> applied in full, by the risk team, with site investigation of the
+crest. <TableReference tableKey="cle-desiccation-screening-table-1" /> summarizes the differences.
+
+<TableVertical
+  tableKey="cle-desiccation-screening-table-1"
+  alt="Comparison of the CLE desiccation screening model and a detailed assessment"
+  caption="Comparison of the CLE desiccation screening model and a detailed assessment."
+  headers={[[{ value: 'Aspect' }, { value: 'Screening Model' }, { value: 'Detailed Assessment' }]]}
+  columns={[
+    ['Purpose', 'Probability of a continuous crack', 'Crack depth', 'Initiation', 'Progression'],
+    [
+      'Screening-level risk assessment',
+      'Scored from surface layer, climate, and crest soil, with an observation override',
+      'Tabulated by climate, soil, and surface layer',
+      '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 from site investigation of the crest',
+      'Shear stress analysis of the crack geometry',
+      'Assessed by the risk team, informed by the same tables',
+    ],
+  ]}
+/>
+
+The screening model does not estimate the width of the crack. Crack width enters a detailed shear stress analysis of initiation, but the screening
+model's initiation gate depends only on the bottom-of-crack elevation, so no width is needed.
+
+## Place Among the CLE Screening Models
+
+The desiccation model is one of the four crest-crack models of the CLE family, together with cross-valley differential settlement, differential
+settlement adjacent to a wall or cliff, and frost cracking (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 CLE
+Common Methods manual). Its flaw is a transverse crack open at the crest, and it shares with the other crest-crack models the headwater initiation
+gate, the pool-dependent failure-pathway gates, and the form of its results. It differs from them in its flaw assessment:
+
+- Its three factors describe the crest surface, the climate, and the crest soils rather than settlement or geometry.
+- Its crack depth comes from a table by climate, soil, and surface layer rather than from the settlement of the embankment.
+- It is one of the two models, with frost cracking, that apply a lower threshold to the weighted sum and that treat the mechanism as inapplicable
+  when every crest soil is a clean or nearly clean sand or gravel.
+
+<CitationFootnote />