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  <xsd:element name="NoncashOrPartNoncashAcquisitionContingentConsideration" id="wldn_NoncashOrPartNoncashAcquisitionContingentConsideration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="EarningsBeforeInterestTaxesDepreciationAndAmortization" id="wldn_EarningsBeforeInterestTaxesDepreciationAndAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="BusinessCombinationContingentConsiderationArrangementsEarnoutPaymentsMaximumPayout" id="wldn_BusinessCombinationContingentConsiderationArrangementsEarnoutPaymentsMaximumPayout" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="BusinessCombinationContingentConsiderationArrangementsEarnoutPaymentsEarnoutPeriod" id="wldn_BusinessCombinationContingentConsiderationArrangementsEarnoutPaymentsEarnoutPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="CreditAgreement2023AmendedAndRestatedCreditAgreement05May2025Member" id="wldn_CreditAgreement2023AmendedAndRestatedCreditAgreement05May2025Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CreditAgreement2023AmendedAndRestatedCreditAgreement05May2025TermLoanMember" id="wldn_CreditAgreement2023AmendedAndRestatedCreditAgreement05May2025TermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CreditAgreement2023AmendedAndRestatedCreditAgreement05May2025RevolvingCreditFacilityMember" id="wldn_CreditAgreement2023AmendedAndRestatedCreditAgreement05May2025RevolvingCreditFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RepaymentsOfLinesOfCreditRetirePriorCreditAgreement" id="wldn_RepaymentsOfLinesOfCreditRetirePriorCreditAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="BusinessCombinationConsiderationTransferredPurchasePriceSubjectToHoldbacksAndAdjustments" id="wldn_BusinessCombinationConsiderationTransferredPurchasePriceSubjectToHoldbacksAndAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AccountingStandardsUpdate202503Member" id="wldn_AccountingStandardsUpdate202503Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AccountingStandardsUpdate202506Member" id="wldn_AccountingStandardsUpdate202506Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CommitmentsAndVariableInterestEntitiesAbstract" id="wldn_CommitmentsAndVariableInterestEntitiesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AccountingStandardsUpdate202511Member" id="wldn_AccountingStandardsUpdate202511Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AccountingStandardsUpdate202512Member" id="wldn_AccountingStandardsUpdate202512Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AccountingStandardsUpdate202509Member" id="wldn_AccountingStandardsUpdate202509Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CompassMunicipalAdvisorsLlcMember" id="wldn_CompassMunicipalAdvisorsLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuableContingencyClosingAveragePricePerShare" id="wldn_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuableContingencyClosingAveragePricePerShare" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="SouthernCaliforniaEdisonAndNewYorkPowerAuthorityMember" id="wldn_SouthernCaliforniaEdisonAndNewYorkPowerAuthorityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BurtonEnergyGroupLlcMember" id="wldn_BurtonEnergyGroupLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuableClosingAveragePricePerShareTradingDaysImmediatelyPrecedingThirdTradingDayPriorToClosing" id="wldn_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuableClosingAveragePricePerShareTradingDaysImmediatelyPrecedingThirdTradingDayPriorToClosing" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentOfTotalRevenueComprisedOfContractsWhichIncludeSeparatePhasesOrElementsLowEndOfRange" id="wldn_PercentOfTotalRevenueComprisedOfContractsWhichIncludeSeparatePhasesOrElementsLowEndOfRange" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentOfTotalRevenueComprisedOfContractsWhichIncludeSeparatePhasesOrElementsHighEndOfRange" id="wldn_PercentOfTotalRevenueComprisedOfContractsWhichIncludeSeparatePhasesOrElementsHighEndOfRange" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ContractWithCustomerLiabilityRetainage" id="wldn_ContractWithCustomerLiabilityRetainage" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
</xsd:schema>
