feat(VMR0015): real AMS-III.AV. equations + dry-run validation (Safe Drinking Water dMRV)

[BikramBiswas786]

VMR0015 v1.0 — Safe Drinking Water dMRV (Hedera Guardian)

Guardian implementation of Verra VMR0015 v1.0 — Revision to AMS-III.AV.: Low Greenhouse Gas Emitting Safe Drinking Water Production Systems (active since 31 Oct 2025; replaces standalone AMS-III.AV.). Built for the DLT Earth Methodology Bounty Program.

TL;DR — what changed since last review

• The on-chain calculation is now driven end-to-end: a Monitoring Report submitted with the Emission Reductions field left blank has its value computed by the policy and minted — no manually entered credit amounts.
• Validated against a real Verra project, VCS 3599 (Grouped Projects for Safe Drinking Water for Schools in Viet Nam): the policy reproduces ER = 154,125.14 tCO₂e → 154,125 VCU, matching the registry issuance.
• Added a policy integrity test (runnable, 9/9 pass) and a VMR0015 v1.0 provision-alignment document.

1. What the policy does

1. Onboards Project Proponent, VVB, and Standard Registry roles.
2. Collects baseline/project monitoring data via the Monitoring Report schema.
3. Runs the AMS-III.AV. equations on-chain to derive BE, PE, LE and ER.
4. Enforces the VMR0015 §6.1 water-quality gate (>10% appliance failure → ER = 0, fail-closed).
5. Routes the report through VVB verification → SR approval → token mint, producing a Verifiable Presentation and Trustchain.

2. On-chain equations

SEC  = 357.48 / nwb                                                  [AMS-III.AV Eq.5]
BE_y = QPW_y × m × X_boil × SEC × (BL_fuel × f_i × EF_fuel × 1e-9)  [Eq.1]
ER_y = BE_y − PE_y − LE_y                                            [Eq.7]
Water-quality gate: pass_rate < 0.90 → ER_y = 0  (fail-closed)      [§6.1]

Parameter → Monitoring Report field mapping:

Parameter	Field		Parameter	Field
QPW_y	field12		f_i (fNRB, TOOL33)	field17
m	field13		BL_fuel	field18
X_boil	field14		PE_y	field4
nwb	field15		LE_y	field5
EF_fuel	field16		BE_y (computed)	field3
WQ pass/total	field10/field11		ER_y (computed, mint rule)	field6

3. Verified result — real Verra project (VCS 3599)

Test data is grounded in VCS 3599, a registered Verra safe-drinking-water project in Vietnam (linked to the World Bank Emission Reduction-Linked Bond for clean water). Parameters were back-calculated from the project's verified ER spreadsheet so the on-chain equations reproduce the registry figure.

Monitoring period: 01 Jan – 30 Jun 2025.

Inputs: QPW=713,972,729 L | m=0.95 | X_boil=1.0 | nwb=0.10
        EF=81.6 tCO2/TJ | f_i=0.82 | BL_fuel=1.0 | PE=0 | LE=8,116 | WQ=95/100

SEC  = 357.48 / 0.10 = 3,574.8
BE_y = 162,241.14 tCO2e
ER_y = 162,241.14 − 0 − 8,116.00 = 154,125.14 tCO2e  →  154,125 VCU

This matches the Verra registry issuance for VCS 3599.

4. Live dry-run evidence (the calculation is policy-driven, not entered)

Hedera testnet dry-run, 2026-06-14, policy instance 6a2eb894…, token 0e34f609…:

Stage	Document	Signer (role)	Result
Submit	MR bf772a1e	PP	ER field left blank → calc injected field3=162241.14, field6=154125.14
Verify	MR 4f777343	VVB	values preserved
Approve	MR (final)	SR	values preserved
Mint	MintToken 4c4f77e8	SR	amount = 154125.14
Trustchain	VP 698899da	SR	bundles MR + MintToken

The signed VCs are included under evidence/. The minted amount equals the computed ER — confirming the methodology equations drive issuance.

A second control run (deliberately tiny inputs, ER computes negative) minted 0.00, demonstrating the conservative floor and that the value is genuinely computed, not echoed from input.

5. Policy integrity test

tests/policy_integrity_test.js embeds the verbatim calculate_report_fields expression from the policy binary and asserts behaviour (run node policy_integrity_test.js, exit 0 = pass). 9/9 pass:

• Canonical VCS 3599 → 162,241.14 / 154,125.14 / 154,125 VCU
• WQ gate: 85% → 0, 90% boundary → credits, no sampling → 0
• nwb=0 → BE 0; PE+LE>BE → ER 0 (no negative credits)
• Typed field3/field6 overwritten by computed values (cannot mint arbitrary amounts)

6. VMR0015 v1.0 alignment

See docs/VMR0015_v1.0_provision_alignment.md for a provision-by-provision map (leakage adjustment factor set at validation; fNRB via TOOL33; REDD+ double-counting assessment — N/A for a water-purification project; interacting-technologies baseline via X_boil; §6.1 gate).

7. Repository contents

Emission Reductions from Safe Drinking Water Supply/
├── policy/        VMR0015 ...1781446804289.policy  (the validated instance)
├── schemas/       16 schemas (xlsx export included)
├── formulas/      formula.json, VMR0015_formula.zip
├── tests/         policy_integrity_test.js  (+ canonical fixture, dry-run record)
├── docs/          VMR0015_v1.0_provision_alignment.md
├── evidence/      signed VCs: PUBLISH, MR (submit/verify/approve), MintToken, VP
└── workflow.png   PP → VVB → SR → mint lifecycle

8. How to review

1. Math: open formulas/formula.json, cross-check calculate_report_fields.
2. Reproduce: node tests/policy_integrity_test.js → 9/9 pass, canonical = 154,125.
3. On-chain: inspect evidence/ — MR (field6 computed) → MintToken (154125.14) → VP.
4. Alignment: docs/VMR0015_v1.0_provision_alignment.md.

Test data is a real Verra project (VCS 3599), 2025 H1, and the on-chain result matches the registry issuance.

"proof": {
"type": "Ed25519Signature2018",
"created": "2026-06-14T16:55:14Z",
"verificationMethod": "did:hedera:testnet:HA7FYHQfHYXcMkZgyjVKyELNLKCYkcb1UsN1dToLMFu1_0.0.9222530#did-root-key",
"proofPurpose": "assertionMethod",
"jws": "eyJhbGciOiJFZERTQSIsImI2NCI6ZmFsc2UsImNyaXQiOlsiYjY0Il19..Ux_GmzLnGZJlzXkVB88SEL1pvhIPmN5F6wSzpxbAHBK1zNrPYMdj8nr64sQQAPJwZK6XZyW7HDG5_4scJX4hBA"
}
}

[BikramBiswas786]