<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>060400 - Disclosure - Supplemental Cash Flow Information</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>c20130101to20130630</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000021828</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>us-gaap_SupplementalCashFlowInformationAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Supplemental Cash Flow Information [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_CashFlowSupplementalDisclosuresTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="c20130101to20130630" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family: 'Times New Roman', Times, serif; font-size: 10pt;"&gt;&lt;div style="text-align: justify;"&gt;&lt;table cellpadding="0" cellspacing="0" class="DSPFListTable" style="width: 100%; font-family: 'Times New Roman', Times, serif; font-size: 10pt;"&gt;&lt;tr&gt;&lt;td style="width: 36pt; font-family: ''Times New Roman'', Times, serif; font-size: 10pt; vertical-align: top; align: right;"&gt;4.&lt;/td&gt;&lt;td style="text-align: justify; width: auto; font-family: ''Times New Roman'', Times, serif; font-size: 10pt; vertical-align: top;"&gt;&lt;u&gt;Supplemental Cash Flow Information&lt;/u&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="text-align: justify; text-indent: 36pt; font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;&amp;#160;&lt;/div&gt;&lt;div style="text-align: justify; text-indent: 36pt; font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;The following is supplemental information relating to the condensed consolidated statements of cash flows:&lt;font style="font-size: 6pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;div style="text-align: justify; text-indent: 36pt; font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;&amp;#160;&lt;/div&gt;&lt;table align="center" border="0" cellpadding="0" cellspacing="0" style="width: 90%; font-family: 'Times New Roman', Times, serif; font-size: 10pt;"&gt;&lt;tr&gt;&lt;td valign="bottom" style="width: 66%; vertical-align: top;"&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="6" style="white-space: nowrap; vertical-align: top;"&gt;&lt;div style="text-align: center; font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;For the Six Months Ended&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td valign="bottom" style="padding-bottom: 2px; width: 66%; vertical-align: top;"&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="padding-bottom: 2px; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="2" style="border-bottom: #000000 2px solid; white-space: nowrap; vertical-align: top;"&gt;&lt;div style="text-align: center; font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;June 30, 2013&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; padding-bottom: 2px; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="padding-bottom: 2px; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="2" style="border-bottom: #000000 2px solid; white-space: nowrap; vertical-align: top;"&gt;&lt;div style="text-align: center; font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;June 30, 2012&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; padding-bottom: 2px; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td valign="bottom" style="width: 66%; vertical-align: top;"&gt;&lt;div style="text-align: left; text-indent: -7.2pt; font-family: ''Times New Roman'', Times, serif; margin-left: 7.2pt; font-size: 10pt;"&gt;Cash paid during the period for:&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="2" valign="bottom" style="vertical-align: top;"&gt;&lt;div&gt;&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="2" valign="bottom" style="vertical-align: top;"&gt;&lt;div&gt;&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td valign="bottom" style="background-color: #cceeff; width: 66%; vertical-align: top;"&gt;&lt;div style="text-align: left; text-indent: -7.2pt; font-family: ''Times New Roman'', Times, serif; margin-left: 16.2pt; font-size: 10pt;"&gt;Interest&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;$&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="text-align: right; background-color: #cceeff; width: 9%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;315,301&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;$&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="text-align: right; background-color: #cceeff; width: 9%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;309,053&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td valign="bottom" style="background-color: #ffffff; width: 66%; vertical-align: top;"&gt;&lt;div style="text-align: left; text-indent: -7.2pt; font-family: ''Times New Roman'', Times, serif; margin-left: 7.2pt; font-size: 10pt;"&gt;Supplemental disclosure of non-cash financing activities:&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="background-color: #ffffff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: left; background-color: #ffffff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: right; background-color: #ffffff; width: 9%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; background-color: #ffffff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="background-color: #ffffff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: left; background-color: #ffffff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: right; background-color: #ffffff; width: 9%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; background-color: #ffffff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td valign="bottom" style="background-color: #cceeff; width: 66%; vertical-align: top;"&gt;&lt;div style="text-align: left; text-indent: -7.2pt; font-family: ''Times New Roman'', Times, serif; margin-left: 16.2pt; font-size: 10pt;"&gt;Note issued for purchase of fixed assets&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;$&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="text-align: right; background-color: #cceeff; width: 9%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;27,464&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;td valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;$&lt;/div&gt;&lt;/td&gt;&lt;td valign="bottom" style="text-align: right; background-color: #cceeff; width: 9%; vertical-align: top;"&gt;&lt;div style="font-family: ''Times New Roman'', Times, serif; font-size: 10pt;"&gt;83,715&lt;/div&gt;&lt;/td&gt;&lt;td nowrap="nowrap" valign="bottom" style="text-align: left; background-color: #cceeff; width: 1%; vertical-align: top;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>The entire disclosure for supplemental cash flow activities, including cash, noncash, and part noncash transactions, for the period. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 230

 -SubTopic 10

 -Section 50

 -Paragraph 4

 -URI http://asc.fasb.org/extlink&amp;oid=6367179&amp;loc=d3e4313-108586



Reference 2: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 230

 -SubTopic 10

 -Section 50

 -Paragraph 3

 -URI http://asc.fasb.org/extlink&amp;oid=6367179&amp;loc=d3e4304-108586



Reference 3: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Statement of Financial Accounting Standard (FAS)

 -Number 95

 -Paragraph 32

 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 230

 -SubTopic 10

 -Section 50

 -Paragraph 5

 -URI http://asc.fasb.org/extlink&amp;oid=6367179&amp;loc=d3e4332-108586



</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Supplemental Cash Flow Information</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>Supplemental Cash Flow Information</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://colonialcomm.com/role/SupplementalCashFlowInformation</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
