the write-off of $6 million of unamortized deferred financing costs, partially offset by $2 million of unamortized premium. There was no loss on early extinguishment of debt for the six months ended June 30, 2022.
Income tax expense. Income tax expense remained relatively consistent for the six months ended June 30, 2021 and 2022 at $57 million and $54 million, respectively, which reflects effective tax rates of 25.7% and 25.5%, respectively.
Net income. Net income decreased by 3%, from $164 million for the six months ended June 30, 2021 to $159 million for the six months ended June 30, 2022 primarily due to (i) a decrease in low pressure gathering revenues, (ii) lower fresh water delivery revenues, (iii) higher direct operating expenses, (iv) higher depreciation expense, (v) higher general and administrative costs and (vi) higher interest expense, partially offset by higher equity in earnings of unconsolidated affiliates and increased other fluid handling revenues. In addition, the six months ended June 30, 2021 included a loss on early extinguishment of debt for the redemption of the 2024 Notes, and there was no loss on early extinguishment of debt during the six months ended June 30, 2022.
Adjusted EBITDA. Adjusted EBITDA decreased by 3%, from $444 million for the six months ended June 30, 2021 to $430 million for the six months ended June 30, 2022. The decrease between periods was primarily due to (i) a decrease in low pressure gathering revenues, (ii) lower fresh water delivery revenues, (iii) higher direct operating expenses and (iv) higher general and administrative costs, excluding equity-based compensation expense, partially offset by higher other fluid handling revenues. For a discussion of the non-GAAP financial measure Adjusted EBITDA, including a reconciliation to its most directly comparable financial measure calculated and presented in accordance with GAAP, read “—Non-GAAP Financial Measures” below.
Capital Resources and Liquidity
Sources and Uses of Cash
Capital resources and liquidity are provided by operating cash flow and available borrowings under our Credit Facility and capital market transactions. See Note 7—Long-Term Debt to the unaudited condensed consolidated financial statements. We expect that the combination of these capital resources will be adequate to meet our working capital requirements, capital expenditures program, expected quarterly cash dividends and share repurchases under our share repurchases program for at least the next 12 months.
Our Board of Directors (the “Board”) declared a cash dividend on the shares of our common stock of $0.2250 per share for the quarter ended June 30, 2022. The dividend will be payable on August 10, 2022 to stockholders of record as of July 27, 2022. Our Board also declared a cash dividend of $138 thousand on the shares of Series A Preferred Stock, which will be paid on August 15, 2022 in accordance with their terms, which are discussed in Note 11—Equity and Earnings Per Common Share. As of June 30, 2022, there were dividends in the amount of $69 thousand accumulated in arrears on our Series A Preferred Stock.
We expect our future cash requirements relating to working capital, capital expenditures and quarterly cash dividends to our stockholders will be funded from cash flows internally generated from our operations or borrowings under the Credit Facility.
As of June 30, 2022, we did not have any off-balance sheet arrangements.
Cash Flows
The following table summarizes our cash flows for the six months ended June 30, 2021 and 2022:
| | | | | | | |
| | Six Months Ended June 30, | |
(in thousands) | | 2021 | | 2022 | |
Net cash provided by operating activities | | $ | 360,375 | | | 354,181 | |
Net cash used in investing activities | | | (73,704) | | | (162,692) | |
Net cash used in financing activities | | | (286,633) | | | (191,489) | |
Net increase in cash and cash equivalents | | $ | 38 | | | — | |
Operating Activities. Net cash provided by operating activities was $360 million and $354 million for the six months ended June 30, 2021 and 2022, respectively. The decrease in cash flows provided by operations between periods was primarily the result of decreased low pressure gathering revenues, higher direct operating expenses, partially offset by changes in working capital, excluding income tax receivable, and higher other fluid handling revenues between periods. Additionally, we received income tax refunds during